Annual report 2019 2 RoCS Annual report 2019 1 Members of the centre 3

Contents 1 06 From the Director Annual report 2 08 Towards understanding: RoCS goals 3 10 Glimpses from the life at RoCS

2019 10 A day in the life at RoCS 11 A day in the Sun – 12 Inversion 13 The Frontier Development Lab (FDL) 14 DKIST 15 Steering the gaze of IRIS 16 WaLSA

4 18 2019 activities by theme

20 Simulations 22 Observations with SST and IRIS 24 Solar science with ALMA 28 New code developments 30 Outreach

5 32 International Rosseland Visitor Programme

6 Contact 34 Members of the centre Svein Rosselands hus

Sem Sælands vei 13 7 NO-0371 Oslo 44 Appendices

Norway 44 Talks and presentations 2019 P.O. box 1029 Blindern 47 Papers in refereed journals 2019 NO-0315 Oslo Norway To understand the origin and evolution of the solar 1 magnetic field on spatial scales ranging from the Rosseland Centre for smallest observable (<100 km) to the size of active Solar Physics (RoCS) regions (100,000 km). To understand the dynamic structuring and mass – 2 and energy transfer in the solar atmosphere from the relatively cool (6,000 K) surface to the multi- million degree corona.

To understand which configurations of the magnetic 3 field, ambient and emerging, lead to the develop- ment of dynamic phenomena such as surges, jets Our vision is and flares of all sizes that permeate the active solar atmosphere. understanding the workings of the To go beyond the single-fluid magnetohydrodynamic 4 energetic Sun. (MHD) paradigm, which breaks down in the nearly neutral chromosphere and the almost collisionless coronal plasma. We will do this by applying multi-­ fluid and particle-in-cell techniques, providing new understanding of heating and particle acceleration in both quiet and active solar environments. 6 RoCS Annual report 2019 1 From the Director 7 M. D’Angelo, ITA

"The Sun, with all those planets re- volving around it and dependent on it, can still ripen a bunch of grapes as if it had nothing else to do."

Galileo Galilei

CAT-7 cabling, mechanical ventilation of the from University of St.Andrews. These hir- For the first annual report (2018) we had larger rooms enabling more people in an ings expand our scientific profile in very a presentation of the vision and scientific open landscape, sound-absorbing material exciting ways. Another important activity programme of the centre. This year we on the walls with astronomical pictures here is our International Rosseland Visitor have selected to give some glimpses from printed on them and a RoCS kitchen and Programme, which is described in more the life at RoCS in Section 3. meeting rooms in the old library storage detail in Section 5. rooms. A number of exciting results have been During 2019 we have also worked to obtained in 2019. A selection of these are The new facilities were celebrated with strengthen internal collaboration with- reported on in this annual report in Sec- From the opening of the new facilities, November 1 2019. From left: Viggo Hansteen (PI), Sven Wedemeyer (PI), a two-day RoCS gathering, November in the centre. Apart from the “advance” tion 4 with a full list of papers published Tiago Pereira (PI), Luc Rouppe van der Voort (PI), 28-29, and an official opening ceremony and the November gathering mentioned in refereed journals in Appendix 2. We Benedikte Karlsen (RoCS coordinator), with speeches by the dean of the Faculty above, we continued our active part in a published 53 papers in refereed journals Boris Gudiksen (PI) and Mats Carlsson (director). of Mathematics and Natural Sciences, pilot project on career development for in 2019, up from 38 in 2018. From the Director Morten Dælen, the Research Council of temporary researchers. This is in collab- Norway through Liv Furuberg, the head of oration with other centres of excellence in As the most important part of a centre is the Institute of Theoretical Astrophysics, Oslo, after the initiative from the Hylleraas people, we have short presentations of all – Per Lilje, and the RoCS director. The two- Centre for Molecular Quantum Chemis- the members in Section 6. day gathering featured short talks by all try. A group has been formed at RoCS to This is the second annual report of the Rosseland Centre for Solar scientific personnel at RoCS with focus implement the ideas we got through this Adding to our substantial involvement Physics (RoCS). The centre is one of the 10 centres of excellence on on-going work. Although the program project. One of the results is the formation in the Hinode/EIS and IRIS space borne was packed with 24 talks, the feedback of a “parliament” formed by the postdoc- observatories, RoCS takes part in the selected by the Research Council of Norway in the fourth round was very positive. We also had a workshop toral researchers and PhD students, with Solar Orbiter mission of ESA/NASA with co- of the centres of excellence scheme. on harassment issues which raised our monthly representation at the PI meetings. investigator status on the instrument PHI awareness in a very important area. We have also strengthened the on-boarding and co-Principal investigator status on programme for new employees, both with SPICE. The PRITS (Project Related IT Ser- In 2019 the ramp-up of activities contin- improved written material and through the vices) group of the institute is responsible The year started in temporary premises at rooms meant that such collaborations could jects were followed by group discussions ued. Two postdoctoral researchers and appointment of a mentor from the group of for the pipeline translating telemetry into Ullevål stadium (the national soccer stadi- take place with minimal disturbances for on a selected number of them. four PhD students started. The possibility temporary researchers for each newcomer. scientific images for SPICE and a function- um of Norway), while our home building, the others. We also got a group feeling just through a centre to attract leading scien- ing pipeline was completed in 2019. At the Svein Rosseland’s house at Blindern, un- from the fact that we started from scratch, After ten months at Ullevål, we could fin­ tists to come for shorter or longer visits The European Research Council (ERC) syn- time of writing, Solar Orbiter has been derwent renovation. At Ullevål we were away from the usual offices. ally move back, on November 1st 2019, has often been highlighted as one of the ergy grant WHOLE SUN had its kick-off successfully launched (February 5, 2020) sitting in an open landscape (except for exactly two years after the start of RoCS. most important aspects by other centres of meeting in May 2019. In this project we and the instruments have been switched myself and the centre coordinator, who During this period, we had the second re- Moving in took a week with a lot of hard excellence. We completed a contract with work with groups in Paris, Göttingen, St. on, one by one. We are heading for very had our own offices). The whole Institute treat of RoCS. Since we actually didn’t go work put in by our administrative and the University of Copenhagen, enabling Andrews and Tenerife. One of the goals exciting times in the years to come. of Theoretical Astrophysics had such open anywhere (stayed at Ullevål) and “retreat” technical staff, while the rest of us were professor Åke Nordlund to work 20% for is to develop a new code that can treat seating together, on one floor. This went sounds defensive, it was jokingly named working from home or from rooms booked RoCS. Adjunct positions (20%) were also the whole Sun as one system. We are well March 2020 surprisingly well – the open landscape “advance”. The theme of the gathering at the university in various places. The filled with Dr. Juan Martínez Sykora from underway in our development of Bifrost facilitated new collaborations and the was new collaborations and a number of renovation resulted in new paint, com- Lockheed Martin Solar and Astrophysics in the DISPATCH framework as a possible Mats Carlsson, presence of many small and large meeting flash-talks with suggestions for new pro- pletely new wiring of the network with Laboratory and professor Ineke De Moortel solution, see Section 4.4. Director of RoCS 8 RoCS Annual report 2019 2 Towards understanding: RoCS goals 9

Towards understanding: RoCS goals –

New hardware and novel techniques, both computational and observational, promise to revolutionise our understanding of the workings of the entire coupled solar atmosphere. The solar physics group of the Institute of Theoretical Astrophysics (ITA) at the University of Oslo has played a central role in these developments and has also exploited them to make significant contributions at the forefront of solar physics.

The Rosseland Centre for Solar Physics on these exciting developments and drive (RoCS), named after the founder of ITA major breakthroughs in understanding who initiated solar physics research in the interplay between the magnetic field Norway, dramatically expands these efforts and the plasma in the outer solar atmos- to build a comprehensive understanding phere, and the deeply rooted connections of chromospheric and coronal heating and between convective motions in the Sun’s violent solar activity. interior and the structuring and activity Our primary objective of the corona. The investigations are two- is understanding Several recent developments have made pronged: advanced 3D numerical simu- the workings of the the complex physics of the outer solar at- lations, which can be directly compared mosphere tractable to quantitative analy- to high-resolution observations from the energetic Sun. sis. In particular, the development of high ground and from space. Synthetic diag- performance computers has allowed us to nostics are computed from the models and build 3D radiative MHD codes designed compared with high-resolution observa- to treat the physics of the chromosphere tions. The similarities and discrepancies and corona as well as software capable of are used to investigate the role of vari- converting simulation output into synthetic ous physical mechanisms that have been observables. Similarly, the last few years proposed as drivers of the energetics and have seen major progress in extremely dynamics of the active solar atmosphere, high resolution imaging spectroscopy, such as shocks, magneto-acoustic waves, enabled by adaptive optics and image re- magnetic reconnection and various plasma construction techniques, as well as novel instabilities. diagnostics from space based observatories. RoCS is in a unique position to capitalise

Bifrost repository structure (M. Szydlarski, RoCS) 10 RoCS Annual report 2019 3 Glimpses from the life at RoCS 11 D. Nóbrega Siverio, RoCS

A day in the Sun –

Doing observations at the Swedish 1-m Solar Telescope When the optimal conditions arise, energies are flow- (SST) is synonymous with getting up before sunrise ing and everyone gets excited to hit the record button. and greeting the nighttime observers, as they make Since clear, lasting data is not an everyday occurance, their way back from their shifts. As solar observers, we it definitely is the highlight of the day, the days we have the privilege of watching sunrise every morning get it. During a passing of clouds, we may close the as we open the telescope. Each and every morning telescope, and work on our individual research to the Sun will greet us, while its beauty only grows make time pass, until we are able to observe again. larger for every passing day. After opening the tel- As sunset gets near, we make our way up to the roof escope, breakfast will be indulged in the company and lower the telescope and shut it down. We drive of each other, while the Sun can rise to full position. down to the residencia under the dim, purple sky, We make our way down to the basement afterwards, reflecting over the sights of the day. Dinner is served where calibrations will be first on our task list. If the and an early night needed, to prepare for yet another seeing is promising we will spend most of the day in sunrise at SST. the basement, with some breaks in between for food, phone calls and walks in the mountain. Ingrid Marie Kjelseth A day in the life at RoCS "Working in academia, I find it refreshing and fun – to bring our work to pupils; it’s a good opportunity Occupying the second floor of Svein Rosseland’s Hus, the to practice communicating our science in accessi- Rosseland Centre for Solar Physics (RoCS) is sandwiched ble and captivating ways. Young minds are inquisi- between the Extragalactic and Cosmology groups at the Institute tive and demanding: being able to meet them with of Theoretical Astrophysics. Days here begin as they do in all knowledge and insight is important not only for productive institutions: with coffee and good conversations. their growth, but for mine as a budding scientist and educator." Passing through the hallways at ITA, the analyze and learn about the Sun. RoCS process, debrief, and discuss next steps passerby might not notice the unassuming plays host to observational astronomers, for our work as well as our play. Evenings Rebecca Robinson way by which RoCS scientists go about our code developers, specialized theoreticians, wrap up quietly as, one by one, we each work; peeking into any given RoCS office, simulation builders, educators, and lifelong find our respective stopping points for the one would generally find a collection of learners. day. Although we are different people from faces leaning into screens and, more often different places, each of us know that our than not, several pairs of furrowed brows. Throughout the day, it is important that common belief in scientific progress and But it is through those screens that we we take time to confer with our internal our passion for the work will bring us to- maintain and nourish our international collaborators, attend institute seminars, gether tomorrow for another day of Sun. collaborations, collect and process our data, and check in with one another on a regular and develop algorithms by which we can basis. Later, we break again for coffee to Rebecca Robinson 12 RoCS Annual report 2019 3 Glimpses from the life at RoCS 13

Spatial distribution of selected atmospheric parameters inferred from NLTE inversions of DKIST Ca II 8542 A. The observations of a sunspot were taken by the CRISP instrument at the SST. These results are from a preliminary – analysis done with the DeSIRe code. (C. Quintero Noda, RoCS). The Daniel K. Inouye Solar Telescope (DKIST), which cases of which 5 received the highest grade in an April saw first light in late 2019, is the largest solar telescope 2019 assessment (out of a total of 23 cases with such in the World with an aperture of 4 meter. It is an grade) and are involved as collaborators in a multi- American enterprise located in Hawaii that will allow tude of other use cases. With this involvement and science not presently feasible at any other facility. the experience of RoCS researchers with the highest The initial instrumental setups and observations are resolution spectro-polarimetric diagnostics in existence being guided by the key "Critical Science Plan" set today via the Swedish 1-meter solar Telescope, RoCS of documents. This plan is composed, at its core, by is in a unique position to benefit from the DKIST open "science use cases" contributed by solar physicists, data policy (6 months from observations to release for including individuals beyond those of the American non-USA scientists) and in a great position to establish community. Each science use case comprises of a set new and expand existing collaborations targeting of scientific goals and complete scientific motivation, continued leadership in high-resolution Solar Physics. necessary observations to achieve such goals, and a detailed parameterised setup for each of the instru- Vasco Henriques ments that are in commission for the telescope. RoCS researchers have contributed 7 of 81 such science use NSO/AURA/NSF Inversion – Inversion codes fit spectro-polarimetric observations inversion codes, although different in concept and solving the radiative transfer equation in an iterative how they tackle the inversion problem, will be used process. During this process, the code infers the in- on future data from state-of-the-art observatories like formation about the atmospheric physical parameters DKIST and EST 4-m class telescopes. They will allow the allowing us to understand the physics of different solar community to improve their knowledge on the solar features. In the 1990s and early 2000s, those physics, in particular the magnetic field configuration, codes worked mainly under the so-called Local Ther- of solar features from the bottom of the atmosphere modynamic Equilibrium (LTE) approximation. This to upper layers in the chromosphere. approximation is reasonably accurate in the photo- sphere and for certain spectral lines, but it breaks Moreover, we also helped to organise a workshop down when we use spectral lines that are sensitive to called "Stokes inversions under non-LTE conditions" chromospheric phenomena. Fortunately, we have had celebrated at the Stockholm University in Decem- in recent years an advent of new inversion codes that ber 2019. This workshop aimed to bring together the work under non-LTE (e.g. Socas Navarro et al. 2015, community developing inversion codes. We discussed Milic & van Noort 2018, de la Cruz Rodriguez et al. common aspects of the codes, and we cooperatively 2019) that allow overcoming the mentioned limita- learnt from each other. We also expect to have this tions. We are also developing at RoCS, together with kind of workshops regularly, around once per year, various international partners, a non-LTE inversion in the future. code called Departure coefficients Stokes Inversion based on Response functions. All of the mentioned Carlos Quintero Noda 14 RoCS Annual report 2019 3 Glimpses from the life at RoCS 15

The Frontier Development S.Jafarzadeh, RoCS. Lab (FDL) –

The Frontier Development Lab (FDL) is an iteration in data-intensive areas, as well as During the intensive 8 weeks,we had mul- initiative to apply artificial intelligence (AI) partners such as the SETI Institute, Satellite tiple presentations in the form of reviews technologies to space science to push the Applications Catapult, USC MASCLE, and with members of the FDL fraternity, with frontiers of research and develop new tools the University of Oxford. technical partners like Google, IBM and to help solve some of the biggest challenges Intel, and with senior members of the NASA that humanity faces. These range from I was selected to be a part of NASA’s Living Ames Research center. Towards the end the effects of climate change to predicting with our star team working on "expanding of the program, we submitted a techni- space weather, from improving disaster the capabilities of NASA's Solar Dynamics cal memorandum to NASA, followed by response to identifying meteorites that Observatory (SDO)". During the summer, a final technical presentation to the com- could hold the key to the history of our I participated in an intensive 8-week pro- mittee members in-charge. Finally, the universe. FDL is a public-private partner- gram in the Silicon Valley area in California team delivered a TED-style talk at Google ship with NASA in the USA and ESA in together with 3 fellow PhD students and headquarters in Mountain View. Results Europe. They work with commercial part- 3 mentors from science and industry. Our were also published in December at the ners such as NVIDIA, Intel, and Google challenge was to apply advanced state-of- prestigious conference on Neural Informa- Cloud, IBM, Lockheed Martin, SpaceRe- the-art machine learning techniques to tion Processing Systems (NeurIPS) held in sources Luxembourg, KBRWyle, XPrize, enhance the value of SDO. We focussed on Vancouver, Canada. Kx, and Miso Technologies who provide auto-calibration using deep learning and expertise and the computing resources the creation of virtual observations of the Souvik Bose necessary for rapid experimentation and solar corona.

WaLSA is an international science team studying The WaLSA team aims to obtain a comprehensive waves in the lower solar atmosphere (https:// picture of wave propagation in the lower solar Souvik Bose with his fellow FDL “Living with our star” WaLSA.team). RoCS has supported WaLSA through atmosphere, from wave generation in the sub- team members during the presentation of the final WaLSA a generous grant for hosting the kickoff and photospheric layers to their channelling and even- results at Google Headquarters. follow-up team meetings (in January and August tual dissipation in the magnetised outer atmos- – 2019) as well as for data storage facilities. These phere. These studies will be performed using high- have brought together world-leading experts (from resolution observations that will be interpreted, in 8 countries) in observations, instrument design, tandem, with theoretical models and simulations. wave theory, numerical simulations, spectro- polarimetric inversions, and radiative transfer Shahin Jafarzadeh processes, to concentrate research efforts to yield reliable estimates of the energy transported by MHD waves into the upper solar atmosphere, and provide new insights into the wave dissipation mechanisms and their contribution to heating the upper solar atmosphere. 16 RoCS Annual report 2019 3 Glimpses from the life at RoCS 17

Steering the gaze of IRIS Gabriel Pérez (IAC) –

IRIS provides detailed, “zoomed-in” views the mission is literally at the mercy of our missions such as Hinode or even the blaz- of the Sun, unlike instruments such as mouse clicks! Planning can be both stressful ing Parker Solar Probe! And all on tight AIA, which provide a medium-resolution and rewarding. A planner has to juggle the deadlines, so that we can send the plan to view of the whole Sun. This means that a science requirements with the possibilities NASA mission control, who then upload it planner must decide where and how IRIS of the instrument, the amount of on-board to the satellite. It is very rewarding when observes. Unlike the SST, controlling IRIS memory and the satellite's downlink speed, you can precisely point and time IRIS to is not possible in real-time; all commands while trying to guess what the Sun will be catch that powerful flare in great detail! for a whole day (or more) must be uploaded doing the next day! many hours in advance. Tiago M.D. Pereira At the busiest times, we need to coordinate RoCS was the first institution outside the with multiple teams scattered around the US to participate in IRIS planning. In 2019 world. We have had to work with multi- we had two IRIS planners: Souvik Bose and ple telescopes: from the Canary Islands myself. Planning for IRIS is both a privi- to Japan, rocket launches in New Mexico, lege and a great responsibility: the fate of Korean balloon launches, and other space

Illustration of the proposed EST site at Observatorio del Roque de los Muchachos, with the EST telescope and building drawn at the center, near the Swedish 1-m Solar Telescope (lowermost facility) and the William Herschel Telescope (to the top left).

The European Solar Telescope (EST) is the next the funding of construction should be based on a generation 4-m solar telescope in Europe. EST is more mature design. The preparatory phase has EST the top-ranked mid-size project in the ASTRONET now been consolidated, including full contribu- roadmap for infrastructures in Astronomy 2010- tions from Norway and Sweden, and the design is 2030 and was included in the European Strate- progressing with tenders having been issued for – gic Forum on Research Infrastructures (ESFRI) the EST three main systems: the primary mirror Roadmap 2016. The European Solar Telescope has assembly (M1), the telescope structure, pier and a symmetric design with a minimum of instru- enclosure (TS) and the adaptive secondary mirror mental polarisation making it complementary (M2). The Scientific Advisory Group (with three to the off-axis DKIST telescope and ideal for members from RoCS) has finished the update of measuring chromospheric magnetic fields. After the Science Requirements Document, feeding some setbacks in 2019, the project has taken the into the updated technical requirements. First consequences of the criticism that decisions for light for EST is expected in 2028.

Timeline for IRIS observations – the end product of the IRIS planning. (T.M.D. Pereira, RoCS) NASA 18 RoCS Annual report 2019 4 2019 Activities by theme 19

2019 Activities by theme – 20 RoCS Annual report 2019 4 2019 Activities by theme 21

Simulations –

The Bifrost code is designed to model the outer layers of the solar (or stellar) atmosphere and aims to include all the relevant physics needed to interpret and understand the observations.

Modelling the energetic Sun magnetic field are done assuming that the Early stages of flux emergence Intensity from a “small, high-resolution” simulation Understanding active regions, the key play- particles comprising the fluid are charged. In 1917 Ferdinand Ellerman discovered of solar convection with 3 km spatial resolution. This approach leads to the so-called mag- ers in the energetic Sun, regions of the Sun strong brightenings in the wings of the Hα (M. Carlsson, RoCS) where strong magnetic fields have pierced netohydrodynamic (MHD) equations, in- spectral line that seemed to occur in the the surface, the photosphere. These fields corporated in the Bifrost code, including vicinity of newly formed active regions. rise up into the outer atmosphere where the extensions to the MHD approximation These brightenings eventually became Vertical magnetic field in the photosphere during their interactions, both self-interactions necessary to model the outer solar atmos- known as Ellerman bombs. In 2014 a sim- phere with some fidelity: Optically thick a flux emergence event and the atmospheric and interactions with pre-existing ambient ilar phenomena, named UV-bursts, was temperature response as the field expands through fields, are the source of most, if not all, radiative transfer to model the primary seen in the Si IV and Mg II spectral lines the photosphere and into the chromosphere and activity. In order to build numerical mod- radiative energy loss process from the pho- observed with IRIS, in principle both formed corona carrying cool chromospheric material to tosphere (Sunlight!), thermal conduction, great heights.(V. Hansteen, RoCS) els of the life of active regions one needs far from the site of formation of Hα’s wings. to understand the physical laws of how which is the most important term in the These brightenings were clearly related. magnetic fields and the hot gases of the energy equation in the tenuous corona, And more importantly were giving clues solar atmosphere relate to each other and optically thin radiative losses from the chro- as to how active regions are formed from a numerical scheme to put these laws into mosphere, transition region, and corona. the emerging magnetic field. But how? Photospheric, chromospheric, and coronal intensities play. One can choose one of several levels Bifrost simulations of flux emergence into MHD solver in hand, it is necessary to set as modeled in a “large, low-resolution” simulation of approximation depending on the specific an atmosphere containing a pre-existing with a grid size of 100 km, designed to study the mechanism(s) that is being studied. the boundary conditions: How much mag- ambient field were able to reproduce both importance of large scale structure in forming the netic field should we include in our models, Ellerman Bombs and UV-bursts and show outer solar atmosphere. (V. Hansteen, RoCS) In the simplest case the gases of the solar what shape should it have? These choices them to be a result of the reconnection of atmosphere are treated as a single fluid, are partly constrained by observations of newly emerging fields at different heights and the interactions of this fluid with the the Sun, partly by the type of region or in the bloated chromosphere formed by phenomena that is to be studied. emerging fields. both. At what scale do we need to study is partially ionized, meaning that ions and it imposes on the numerical modeling. In the photosphere in order to pick up these neutrals can drift with respect to each other fact, most theoretical studies about these Big models, small models motions? What is the importance or role breaking the total coupling between the processes are focused on either one or the The Sun operates on many scales from of large scale, several tens of megameters, constituent microscopic species usually other process, but not together. the microscopic to the gigantic, and it is magnetic structures, in the heating of the assumed for the plasma. With respect to important to be able to assess what the corona? Bifrost models spanning spatial res- the nonequilibrium ionization, it is relevant In 2019, the RoCS group accepted the consequences of studying the Sun at a given olutions of 2 km to 100 km and horizontal because in the chromosphere the density challenge, and has been actively involved scale are. For example, models of coronal sizes from 6x6 Mm to 72x72 Mm are being drops orders of magnitude in comparison in unraveling the joint role of those two heating require an understanding of how run to investigate these questions. with the photosphere. This decrease hugely processes on the dynamics and thermody- magnetic fields are churned by convec- impacts on the transition rates, which will namics of the chromosphere and transition tive motions in the photosphere which can (Further) Beyond MHD be substantially slower, leading to large region, and more specifically, in magnet- lead to waves or the tangling of magnetic As stated above, the solar atmosphere is departures in the number densities of the ic flux emergence processes, shocks, and fields in the chromosphere and corona or characterized by an interplay of complex computed ions and neutrals when com- spicules. To that end, new code has been physical processes such as magnetic re- pared with a statistical equilibrium ap- developed to combine in an efficient way connection, radiation, thermal conduction, proximation. Even though both, ion-neutral the interaction between ionized and neu- amongst others. In particular, in the chromo- interactions and nonequilibrium ionization, trals species together with with departures Temperature maps showing the thermal differences sphere, it is of special interest the ion-neu- are key processes in the Sun, understand- of the ionization state from the LTE. Exciting in the shock evolution within an emerged region in a tral interactions and the nonequilibrium ing their effects is challenging due to basic new results have been found that will lead non-equilibrium ionization experiment (left column) uncertainties concerning relevant micro- to a new perspective of the chromosphere and in the same experiment including ambipolar ionization. The ion-neutral interactions diffusion (right column). (D. Nóbrega Siverio, RoCS) are important because the chromosphere physical aspects and the strong constraints in 2020. 22 RoCS Annual report 2019 4 2019 Activities by theme 23

Split image showing a Quiet Sun region in H-beta (top left) and H-alpha (bottom right). This is a nice illustration that the fibrils and spicules are thicker and longer in H-alpha. (J. Joshi, RoCS) Observations with SST and IRIS –

The RoCS group is the largest external user of the Swedish 1-m Solar Telescope (SST) at La Palma in the Canary Islands. All obser- vations are coordinated with the IRIS satellite so that we have dense coverage of the solar atmosphere from the photosphere up through the chromosphere and transition region into the corona. Active region AR12748 observed with the CRISP instrument at the SST on 4 September 2019. At left is an image in H-alpha and at right a map of the magnetic field derived from spectropo- For many years we have an agreement with and associated map of the magnetic field all modern telescopes, the SST employs larimetric observations in the Fe I 617.3 the Institute for Solar Physics in Stockholm are shown in the bottom pair of images an adaptive optics system to correct for nm line. Yellow/red colors indicate neg- which gives us observing time at the SST. on the right. seeing in real time during the observa- ative polarity and blue/green positive polarity. At the interface where the two The observing time is usually spread over tions. Adaptive optics provides a signifi- opposite polarities meet, we observed three 2-week campaigns, in 2019 these For most of the observing days during our cant improvement of the data quality but a small filament eruption (which can campaigns were in May, June, September campaigns, there were no active regions post-facto image restoration is mandatory be seen at left). This event was also and October. These campaigns are very present on the Sun and we focused on quiet to attenuate residual seeing deformations. successfully observed with IRIS. much a team effort and this year 11 RoCS Sun regions. One particular program was With image restoration, high data quality (L. Rouppe van der Voort, RoCS) members participated in the observations. chromospheric observations in the H-beta can be achieved over larger field of view For 6 of them, it was their first time at the line with CHROMIS. These observations and over longer periods of time. Besides SST. We stimulate members of the centre were augmented with CRISP H-alpha im- considerable computing power and data to join observation campaigns. Not only aging and Fe I 6173 spectropolarimetry. The storage capacity, data reduction requires because we need all the help we can get, chromosphere has a striking different mor- a fair amount of manpower and is handled but also because the practical experience of phology in these two spectral lines, see the as a team effort. We collaborate with the observing at the telescope is very valuable top figure on the right. The combined CRISP SST staff in Stockholm and La Palma to in a young scientist’s career. and CHROMIS observations will be used for improve, optimize and further develop the a study on small-scale magnetic reconnec- data processing pipelines for the CRISP and All observations were in coordination with tion events in the lower solar atmosphere. CHROMIS instruments. the IRIS satellite which involves daily in- These are among the smallest scale activity teraction with the IRIS planners to decide processes that can be observed and the SST Magnetic reconnection what target to observe and which observ- has unique capabilities to characterize these Magnetic reconnection is a fundamental participated in a publication on the mag- region. This year, we completed a com- Another highlight in 2019 was the pub- ing program to run. Despite the fact that fundamental physical processes in detail. physical process that is responsible for a netic and thermo-dynamical properties of prehensive study of Ellerman Bombs and lication of an ApJ Letter with RoCS PhD the Sun is currently still in the quiet phase wide variety of dynamical phenomena on penumbral micro-jets lead by Dr. Esteban UV bursts in multiple coordinated SST and Souvik Bose as the lead author. This work of its 11-year magnetic activity cycle, we Data reduction the Sun and is one of the main topics of Pozuelo from Stockholm University. For IRIS datasets, augmented with observations presented the first full characterizations of managed to acquire some good observa- Besides planning and acquisition of new research at RoCS. For example, magnetic this study, spectro-polarimetric observa- from NASA’s Solar Dynamics Observatory. spicules on the disk in the Ca II K line. The tions of active regions. On September 4th, observations, the reduction and data pro- reconnection has been argued to drive a tions from both CRISP and CHROMIS were We further collaborated on a publication by statistical k-means clustering technique we managed to acquire a 3.5 hour time cessing of current and earlier observa- particular type of jet in the chromosphere subjected to advanced inversion techniques. Dr. Vissers from Stockholm University who was used to characterize millions of Ca II series of a small active region. During this tions is one of the other main activities of sunspot penumbrae. We published a conducted extensive multi-line inversions K, H-alpha and Mg II h & k spectral lines. period, a small filament eruption happened of the observations group. We employ detailed study of the dynamical evolution Magnetic reconnection is further mani- of UV bursts combining the Ca II K, Ca II and this event was well covered with the image restoration techniques to mitigate of these so-called penumbral micro-jets fested in so-called Ellerman Bombs in the 854.2 nm and Fe I 630 nm spectral lines CRISP and CHROMIS instruments, as well the effect of atmospheric turbulence (so- based on ultra-high cadence (1 second) ob- lower solar atmosphere and UV bursts in from SST and the Mg II h, k, and triplet as with IRIS. An H-alpha line core image called “seeing”) on the data quality. Like servations in the Ca II H line. We further the upper chromosphere and transition lines and Si IV lines from IRIS. 24 RoCS Annual report 2019 4 2019 Activities by theme 25

A 12m antenna of the Atacama Large Millimeter/sub-millimeter Array (ALMA) at an altitude of 5100m on the Chajnantor plateau in the Chilean Andes with the stratovulcano Licancabur in the background. (S. Wedemeyer, RoCS) Solar Science with ALMA Simultaneous observations of the Sun with ALMA and space-borne telescopes. Left: Single-dish ALMA – scan of the whole Sun (Band 6). Middle: Interferometric ALMA observa- tions (Band 6) of a region on the Sun. Right: Images from different heights in The year 2019 has been a year of expansion for ALMA-related the solar atmosphere as obtained science at RoCS in terms of addressed topics and involved staff. with ALMA, IRIS, Hinode, and SDO. (S. Jafarzadeh, RoCS)

Continued development of the resulting time series covering frequencies such as propagating shock waves or mag- ALMA group in the ALMA receiver bands 3, 6, and 7 will netic reconnection events. The signatures The newly started EMISSA project now be an important test case for the optimi- of shock waves can be seen in the data as complements the ongoing efforts of the sation of SoAP and the development of a dynamic bright or dark features. The chal- Solar ALMA project. EMISSA, short for “Ex- high-cadence solar observing mode for lenges with the identification and tracking ploring Millimeter Indicators of Solar-Stellar ALMA. First experiments with the Solar of these features led to the development Activity” is funded in the FRINATEK pro- ALMA Simulator (SASim) that transforms of automated codes specially designed to gram by the Research Council of Norway, the ART output into artificial observational deal with the peculiarities of ALMA data. and aims at a re-evaluation of stellar activ- measurement sets have been carried out The statistical analysis of the detected fea- ity as observed with ALMA. The new pro- (Szydlarski & Eklund). tures has begun and will, in comparison ject complements our key scientific goal of to observations at other wavelengths, give exploiting ALMA’s diagnostic potential for First scientific results published insight into the origin and physics of the studies of the Sun’s small-scale dynamics The first publication by Jafarzadeh et al. phenomena behind these signatures. with the aim to constrain heating processes (2019) uses SoAP-processed ALMA Band 6 in the solar atmosphere. The group grew mosaic observations of a sunspot in com- Oscillations at millimetre wavelengths to one permanent staff, two researchers, parison with ultraviolet observations from Waves and oscillations are among the prime and three PhD research fellows, of which IRIS, while the first paper using a time se- candidates for the transport of energy and one (Pandit) was newly hired on the EM- ries of a Quiet Sun observations in Band momentum to the upper solar atmosphere. ISSA project. 3 was submitted end of 2019 (Wedemeyer Direct observations of temperature fluc- et al.) The analysed observations were tuations in the solar chromosphere in ac- New scientific tools among the first regular observations of tive and quiet regions with ALMA receiv- The further development of imaging and the Sun with ALMA in 2016. In addition, er bands 6 and 3, were complemented by from ALMA were opposed to those from Presentations, public outreach data processing routines for solar ALMA a “First Spectral Analysis of a Solar Plas- co-observations of the same targets in far synthetic spectra computed from Bifrost and networking data remained a core activity. The Solar ma Eruption Using ALMA” was published and near-ultraviolet with the IRIS and SDO simulations, providing new insights into ALMA Pipeline (SoAP) has been optimized (Rodgers et al.). space telescopes. In the quiet region, a large The SolarALMA project was presented at a the nature of various wave phenomena and and used for processing in a more routine temperature fluctuation above a small net- number of international meetings, including thus their potential role in heating the up- and stable way (Szydlarski). Work on the Observational studies of the dynamic work patch was found with ALMA, while the IAU Symposium 354 in Chile. The latter per solar atmosphere (Jafarzadeh, WaLSA). ESO-funded ALMA development study chromosphere no corresponding temperature excess is was combined with a visit to ALMA and The analysis of early data from ALMA Band observed in the layers above (i.e. as sam- APEX in the Atacama Desert (Wedemeyer). in co-operation with the Nordic ALMA Applications for observations in 2019 Regional Center node at the Onsala Space 3 and Band 6 was continued in 2019 as pled by SDO), suggesting the possibility of The project was also the topic of a public Observatory and Stockholm University, part of PhD projects (Eklund and Guevara energy release in the upper chromosphere. The group was involved as Co-Is in the suc- talk at an Astronomy on Tap event in June Sweden, continued. For this purpose, Gomez) with focus on the small-scale struc- In the active region, the temperature fluc- cessful ALMA observing proposal “3D Struc- 2019. As in the years before, a Norwegian a time series of 3D numerical models of ture and dynamics of the solar chromo- tuations with transverse and line-of-sight ture of the Quiet Solar Chromosphere”. The ALMA Day was organized in spring in co- the solar atmosphere was produced with sphere. ALMA’s spatial and temporal res- velocity oscillations in chromospheric fi- observation, which was to be carried out in operation with the Nordic ALMA Regional Bifrost and then used as input for the Ad- olution make it possible to search the data brils were compared. Furthermore, power ALMA’s observing Cycle 7, included receiver Center node. vanced Radiative Transfer code (ART). The for signatures related to diverse phenomena spectra of the observed wave phenomena bands 3, 6, and the newly offered Band 7.

*The SolarALMA project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No. 682462).

26 RoCS Annual report 2019 4 2019 Activities by theme 27

Roque de los Muchachos, La Palma. (D. Nóbrega Siverio, RoCS) 28 RoCS Annual report 2019 4 2019 Activities by theme 29

A current sheet test for the Ebysus code showing the difference between a single fluid description and a multifluid description. The fractionization of species is obvious. (J. Martínez Sykora, RoCS) New code developments –

One of the main goals for RoCS is to simulate the active sun. That requires a code that is able to incorporate many different kinds of physics to model the varied environment of the Sun, from the deep convection zone to the corona.

To be able to describe an active region en- of our simulation tool set, reaching from number of developers requires that we can The acceleration process requires a fully suited for direct transfer to DISPATCH. The translation of variables across the interface vironment, the numerical code must be advancing our work process to become trust the code to produce correct results, developed PIC simulation and is not yet first basic tests of radiative transfer and between the two sub volumes has been able to handle amongst others, ionization more up to date, integration and inves- and that it is possible to continue the long possible, but meanwhile work has been the multi-physics modules in Bifrost have shown to be not straight forward with the imbalance, radiative transfer, dissipation tigating details of the interplay between running simulations without problems. focused on the transport of the particles and been undertaken and works, even though version of the PIC code that we have avail- of magneto-hydrodynamic waves and the Bifrost and DISPATCH and developing new Any development to our codes now has to their impact on the lower atmosphere. This efficiency has not yet been fully optimized. able. Other implementation methods of chaotic, super-heated environment at the physics modules. pass a number of tests before being allowed new physics module is now implemented Working on optimizing Bifrost for the DIS- PIC have therefore been researched, and center of solar flares. Bifrost is the work- into the working version of the codes. The in Bifrost and is ready to be transferred PATCH framework, made us investigate a evaluations of their potential of handling horse code at RoCS and is able to handle Foundations number of tests is continuously increased into the DISPATCH framework. number of different options for diffusion this problem assessed. which, in the standard Bifrost implemen- many of these physical problems, but In 2019 the code development at RoCS has and now allows us to be more confident Software libraries based on Bifrost tation, was not well suited for DISPATCH. struggles with large ranges in both time primarily been focused on strengthening in the working copy of our codes, making Radiative transfer, thermal conduction and space. Requiring high resolution as the foundation for a more efficient and ro- the growth in the developer base of smaller The testing of Bifrost on large number of and the handling of noise in the magnetic well as spanning a large volume of space bust development cycle and continuous concern. nodes has also been advanced with a col- field are all “global” problems meaning is not possible with the current version so integration of improvements to the nu- laboration with USIT, funded in part by that a simple solution to these problems the code development group at RoCS are merical codes. To strengthen this work, a New physics implemented in Bifrost the Partnership for advanced computing is computationally heavy for Bifrost, but working on transposing most of Bifrost scientific software developer was hired and An integral part of modelling solar active in Europe (PRACE). The goal of the project becomes extremely inefficient when scaling into the DISPATCH framework. Throughout the process of hiring another started during regions is the violent reorganization of the is to develop and test a software library for to hundreds of thousands of CPUs as the 2019, work has advanced on many aspects 2019. The present and foreseen increase in magnetic field which release large amounts halo-exchange that should be more efficient DISPATCH framework would otherwise of energy in a solar flare. This energy is than the standard MPI-library. allow us to do. New methods therefore have released in the form of thermal energy, been investigated to solve these problems energy in different types of waves and high- Development of multi-fluid code in a “local” way that will not impede the ly accelerated non-thermal particles. The The development of a multi-fluid code has scaling of the DISPATCH-Bifrost runs. particles transport a significant amount also advanced in 2019. The Ebysus code is of energy away from the solar flare region based on Bifrost, using most of the internals Adaptive Mesh Refinement (AMR) has also but so far it is not known which accelera- and architecture of Bifrost. In Ebysus it is been investigated. AMR is the ability of the tion mechanism produces these particles. now possible to treat electrons, ions and code to zoom in on locations where higher Including the accelerated particles in our even ion-species and their excitation lev- resolution is needed. This effort is ongoing simulations represents two main problems: els as separate fluids. The final tests were and has been shown to work for easy setups The acceleration process itself and trans- conducted in 2019 and Ebysus should be and it will be further worked on in 2020. port and thermalization of the particles. ready for production in 2020. DISPATCHs ability to switch between dif- Bifrost-DISPATCH integration ferent solution methods is one of the main The integration of Bifrost and DISPATCH arguments for transposing Bifrost into DIS- The acceleration location (blue) and the path(orange) is continuing. 2019 made it clear that the PATCH. The ability of DISPATCH to handle of simulated non-thermal particles in a Bifrost transfer of Bifrost into the DISPATCH frame- using a Particle In Cell method in one sub simulation. (L. Frogner, RoCS) A snapshot from a Bifrost simulation of the solar volume and using a fluid solver in anoth- work was a good opportunity to investigate atmosphere run as a test case in DISPATCH including details of the Bifrost implementation, and er sub volume is critical for the ability to AMR. The black lines show the level of refinement of we realized that certain methods are not handle the simulation of solar flares. The the simulation grid. (A. Popovas, RoCS) 30 RoCS Annual report 2019 4 2019 Activities by theme 31

Ada Ortiz explaining the European Solar Telescope. Outreach (A. Ortiz, RoCS). – Ingrid Marie Kjelseth explaining solar wonders for high school students.(S. Jafarzadeh, RoCS).

RoCS organises and develops different activities and events to promote general awareness of science and, in particular, to spread our understanding of the Sun out among the general public.

EST outreach velocities on the Sun at high resolution and workshop, will represent Norway at the The Institute of Theoretical Astrophysics, how the 4-m aperture of EST “will help us International Olympiad on Astronomy through RoCS, together with 26 institu- understand the twisting motions responsible and Astrophysics. Our Institute and RoCS tions from 18 countries, is a member of the for the generation of vortex flows and waves in jointly organise the Astronomy Olympiad European Association for Solar Telescopes the solar atmosphere“; finally, Clara Froment in Norway. The PI of the project, Shahin (EAST). EAST is in charge of the future discusses coronal rain, arguing that with Jafarzadeh, received a grant from the Re- European Solar Telescope (EST): a next- EST “we will see how small the rain blobs can search Council of Norway to support organ- generation solar telescope, to be located in get and better understand their formation“. isation of the Olympiad in the 2019-2020 the Canary Islands. As part of this ambitious school year. project, the EST consortium is carrying out The EST scientific communications officer a number of outreach activities where RoCS for Norway, Ada Ortiz, has been promot- Through the Astronomy Olympiad, we let participates. The aim is to explain why we ing EST at different levels: together with promising high school students deepen Astronomy” episode of Astronomy on Tap, Froment visited Den Franske Skolen i Oslo, Ada Ortiz gave a summary of her work with need better knowledge of the Sun and how high-level representatives, NASA astro- their passion for astronomy and encourage Ada Ortiz taught us about female astron- and Sneha Pandit and Rebecca Robinson observational astrophysics, and discussed EST will be essential. nauts, and amateur astronomers at the them to study astronomy at university. omers throughout history with “Hidden visited Northern Lights International School. her background and why she became inter- IAU’s 100th anniversary in Brussels, with We not only promote a growing interest in Figures: Amazing women astronomers and their During these visits we taught pupils about ested in astronomy. Ada also wrote about An example of these outreach activities is international researchers at the Flux astronomy and astrophysics by educating legacy.” In the autumn, Rebecca Robinson gravity, planetary and lunar orbits, the her involvement with the European Space the project #TheScienceOfEST, run by a Emergence Workshop held in Tokyo, to the young public, but also build an interna- combined her work in glaciology with her structure of the Sun, spectroscopy, exoplan- Telescope as a member of its scientific ad- team of four EST scientists including RoCS families and children at Forskningstorget tional contact network for the promotion love for astronomy with “Not Just a Cold Dead ets, black holes, and anything else about visory group. researcher Ada Ortiz. #TheScienceOfEST (Oslo’s science fair). In addition, in 2019 of astronomy and astrophysics in schools Rock: exploring exocryospheres.” which they were curious. We have a wealth is a series of short posts written by solar the EST Communications Office“A Tour of of teaching materials including inflatable Clara Froment wrote about her trip to Den scientists that explain, in an accessible way, the Sun: The EST Solar Gallery”, a book made Astronomy on Tap Looking forward, RoCS will continue to planets, spectroscopes, and telescopes that Franske Skolen i Oslo as a visiting educator. interesting solar problems that EST can of stunning images of the sun that will be Astronomy on Tap is a global organisation contribute to Astronomy on Tap events, the students always enjoy. She described her experience with the address. We have periodically published a powerful educational tool. Many of the with a chapter in Oslo, managed by mem- not only by giving talks but also by helping pupils as well as her enjoyment of commu- these posts since May 2018 in social media, images appearing in this book have been bers of our Institute. Astronomy on Tap to organise (Petra Kohutova and Andrius Women in Astrophysics nicating with young students in French, taken by RoCS researchers. It is a showcase and they were very well received by the events are targeted to the general public. Popovas) and advertise them (Shahin Ja- Several RoCS researchers are involved with her native language of the high quality observations that our public. Following the lead from our own In Oslo they include popular talks by sci- farzadeh, Juan C.G. Gomez, Frederik Clem- the in-house Women in Astrophysics blog. scientists work with. Ada Ortiz and Luc Rouppe van der Voort entists, and astronomy quizzes with prizes. mensen, and Rebecca Robinson.) We are This project exists to encourage talented in 2018, more RoCS scientists contributed looking forward to watching Astronomy young women and girls to consider careers new posts in 2019. Daniel Nóbrega-Siverio In 2019, three of the bi-monthly Astronomy on Tap grow in Oslo! in astrophysics, and it’s also a platform Astronomy Olympiad explains how EST will contribute to under- on Tap gatherings were hosted by RoCS for us to write about what we do, why we standing surges: “we will be able to capture The Norwegian Astronomy Olympiad is a researchers. Sven Wedemeyer presented School Visits do it, the challenges we’ve overcome, and the elusive details of the physical processes that national competition for students at up- his ALMA research with “High Tech and During 2019, RoCS researchers visited el- our goals for the future. In 2019, two RoCS lead to surges”; Souvik Bose describes the per secondary schools. The top 5 students, Llamas: Sungazing with the World’s Largest ementary schools on two occasions; Clara researchers contributed posts to the blog. relevance of studying horizontal plasma selected through three rounds of exams/ Telescope.”­ During a special “Women in 32 RoCS Annual report 2019 5 International Rosseland Visitor Programme 33

"Looking in the rear mirror and questioning myself what made the biggest change with the creation and the operation of CIR, I am tempted to say the Visiting Professor programme."

Ludvig M. Sollid, director of Centre for Immune Regulation (CIR). From CIR final report 2007-2017.

WaLSA-team. A team working on waves Jorrit Leenaarts, professor at the Institute in the lower solar atmosphere was hosted for Solar Physics, Stockholm University, during a week in January and a second visited in March to work on multidimen- week in August (see Section 3). A total of 15 sional radiative transfer and the usage of members (Andres Asensio Ramos, Ben Snow, the Multi3D code in Oslo. Bernhard Fleck, David Jess, Elena Khomenko, Gary Verth, Hanna Schunker, Marco Stangalini, Malcolm Druett, postdoc at the Institute for Nazaret Bello González, Oskcar Steiner, Peter Solar Physics, Stockholm University, visited Keys, Richard Morton, Samuel Grant, Samuel in February to work on cork modules for Skirvin, Tony Arber) hosted by Shahin Ja- the Bifrost code. farzadeh visited either one or both weeks. Maryam Saberi took part in the RoCS gath- Atul Mohan. Visited Sven Wedemeyer in ering in November in preparation for a September and worked on ALMA data in postdoctoral position with Sven Wedemeyer preparation for a postdoctoral position he on the ALMA project, starting in 2020. started in 2020. Paola Testa, researcher at Smithsonian International Rosseland Basilio Ruíz Cobo and Maria Esperanza Paez Astrophysical Observatory, visited in April, Maña visited Carlos Quintero Noda in July June and November to work with Luc to work on the inversion code “Departure Rouppe van der Voort, Mats Carlsson and coefficients Stokes Inversion based on Re- other members of RoCS on several projects. Visitor Programme sponse functions” Robert Rutten, emeritus adjunct professor Hugh Hudson, professor from University of of RoCS, visited Luc Rouppe van der Voort – Glasgow, worked with Mikolaj Szydlarski in April to work on solar H-α features with and Mats Carlsson in April on cosmic ray hot onsets. interactions in the solar atmosphere. Valentin Martinez Pillet, director of NSO, Visits from internationally leading scientists are very important João Fernandes, professor from University visited in October-November to work with for the success of RoCS. The International Rosseland Visitor of Coimbra. He spent part of his sabbatical Carlos Quntero Noda and also to inform us in March-June, working on the usage of Ca all on the status of DKIST. Programme is our programme for international exchange, II spectroheliograms from Coimbra and including funds for visits by researchers at professor, post- co-observing with SST. He also worked on Yusuke Kawabata, postdoc at NAOJ, visited doctoral and PhD level for shorter or longer visits to RoCS. the membership of Portugal in EAST and in December to work on inversion codes Portuguese contributions to EST. with Carlos Quintero Noda. 34 RoCS Annual report 2019 16 Members of the centre 35

Members of Phd the centre –

Helle Bakke Frederik Clemmensen Ainar Drews Henrik Eklund The main resource of RoCS and its most important Helle Bakke is a doctoral research fellow Frederik Clemmensen is a doctoral re- Ainar Drews is a doctoral research fellow Henrik Eklund is a doctoral research fel- contributor is our staff. Everyone at our centre, scientific, at RoCS. Helle is at the interface between search fellow at RoCS. The primary topic at RoCS and his research is focused on ob- low at RoCS. His research is focused on administrative and technical, is handpicked because of observations and numerical models, where of Frederik's research are the processes in servations of the Sun. Some of his earlier determining optimal ways to handle inter- their excellent qualifications and expertise. During 2019 she focuses on the effect of accelerated the solar atmosphere that lead to highly work is dedicated to partial automation of ferometric data from ALMA observations particles on the solar atmosphere. In par- energetic, accelerated particles. For this solar observations using simple machine of the Sun. He also makes use of ALMA we had four master students, eleven doctoral research ticular, her research involves comparing purpose, he uses new methods of numerical learning. Ainar’s research revolves around data in combination with space-borne ob- fellows, ten postdocs and researchers, one research soft- synthetic observables to actual observations modelling which he is involved in devel- the investigation of primarily chromospher- servations to study physical phenomena, ware engineer (one more transited from postdoc to RSE of low-energy events in the solar atmos- oping. In general, Frederik is interested ic objects in the penumbrae of sunspots primarily waves motions in the chromo- in March 2020), two associate professors, four professors phere. Helle is an in-house advocate for in programming and developments in called Penumbral Microjets, employing sphere. A strong combination of numerical her coworkers, and she also enjoys pub- computing. both ground- and space- based instruments. simulations and observations is used in his and one centre coordinator. In addition we had five lic education and outreach activities. One work. Henrik is also active in contributing adjunct professors, as well as six associated members of her favorite parts of the job is being a to public outreach. in the administrative and technical staff. Our Scientific teaching assistant. Advisory Committee consisted of 4 members. Two emiriti contributed to publications in refereed journals. Owing to our privileged position as a centre of excellence, we are able to grow in numbers, hiring talented and exceptional researchers of a large number of nationalities. All our members are putting their best efforts into strengthening our scientific achievements, set forward new goals and reach even higher standards for our research.

Souvik Bose Lars Frogner Øystein Håvard Færder Juan Camilo Guevara Gómez Souvik Bose is a doctoral research fellow at Lars Frogner is a doctoral research fellow Øystein Håvard Færder is a doctoral re- As a doctoral research fellow at RoCS, RoCS. Souvik’s research mainly focuses on at RoCS. Lars' research is mainly concerned search fellow at RoCS. He is a part of the Juan Camilo Guevara Gómez is analyz- the dynamics of the solar atmosphere, in with numerical modelling of the solar at- Whole Sun team, and his research is fo- ing solar observations by ALMA seeking particular the origin and the evolution of mosphere, in particular the origin, behavior cused on numerical simulations. During for signatures of heating likely related to spicules in the solar chromosphere. He is and effect of accelerated particles. He is his master, he simulated magnetic activi- propagation of shock waves in the solar mainly an observer and uses data from both generally interested in a range of topics in ty in the quiet Sun atmosphere, and now atmosphere or to reconnection events. Juan ground and space-based solar telescopes software development, including numerical he is experimenting with magnetic flux is also supporting his observational analysis for his research. In addition, he makes use simulations and computer graphics. emergences in the active regions of the by comparing the results with available of numerical radiative transfer codes for solar atmosphere, hoping to generate some simulations. Finally, Juan is also enrolled reproduction of synthetic data to compare UV bursts and surges at the dome-shaped in outreach activities as Astronomy on Tap with the observations. He is also interested magnetic structures that emerges. Oslo and lately in the organization of the in applying machine learning techniques Astronomy Olympiad in Norway. in solar physics. 36 RoCS Annual report 2019 6 Members of the centre 37

Thore Espedal Moe Sneha Pandit Rebecca Robinson Jayant Joshi Petra Kohutova Nancy Narang Thore Espedal Moe is a doctoral research Sneha Pandit is a doctoral research fellow Rebecca Robinson is a new doctoral fellow Jayant Joshi is a postdoctoral researcher at Petra Kohutova is a postdoctoral researcher Nancy Narang is a postdoctoral researcher fellow at RoCS. His focus is on the for- at RoCS. Sneha is mainly analysing observa- at RoCS. Rebecca is using both simulations RoCS. Jayant’s research is mostly focused at RoCS. Petra studies processes responsible at RoCS. Her research primarily includes mation of polarized spectral lines in the tional data taken by ALMA and comparing and observations to analyze the dynamics on measuring the magnetic field in the so- for matter and energy transfer between the study of small-scale features and phe- chromosphere. Taking a forward-modeling it with other well studied observations. She and distribution of the quiet Sun magnetic lar lower atmosphere. His current inter- different layers of the solar atmosphere nomena observed in the solar atmosphere. approach using numerical radiative transfer studies the Sun in order to understand the field and hopes to contribute to our great- est is to understand small-scale magnetic by combining high resolution solar obser- She employs high-resolution observations codes for synthesizing polarized spectra structures of stars in general. The ‘Sun as a er understanding of the coronal energy reconnection events, Ellerman bombs, in vations and numerical simulations. She to understand the dynamics of the small- from the output of Bifrost simulations, he star approach' is to use solar observations budget. She likes to travel, teach, play mu- the lower atmosphere, as well as large- focuses on using thermal instability in the scale events, and to have insights about aims to better understand how and where to estimate properties or features of other sic, go bouldering, eat waffles, drink coffee, scale reconnection events, flares. Jayant is solar atmosphere as a means to probe the their role in the mass and energy cycle of these lines are formed, and how they can stars and in the process understanding the and explore new places and ideas. She is mainly an observer, and he makes use of nature of the coronal heating. She also stud- the solar atmosphere.. be used to diagnose magnetic phenomena. Sun and stars in general a little better. She enjoying her new position with RoCS and both ground-based and space-borne solar ies waves in the solar atmosphere and their wants to learn more about the solar-stellar is looking forward to the coming years. telescopes. role in the energy transport. observations and different techniques of data analysis and simulations. She enjoys Postdocs and contributing towards outreach activities. researchers

Clara Froment Vasco Henriques Shahin Jafarzadeh Daniel Nóbrega Siverio Ada Ortiz Carlos Quintero Noda Clara is mainly investigating the processes Vasco Henriques is a researcher at RoCS. Shahin Jafarzadeh is a researcher in the Daniel Nóbrega-Siverio is a postdoctoral Ada Ortiz is a researcher at RoCS. She stud- Carlos Quintero Noda is a postdoctoral re- that heat the outer layer of the Solar at- Vasco investigates poorly understood dy- Solar ALMA project. He is predominant- researcher at RoCS. He studies the role ies the process of magnetic flux emergence searcher at RoCS. He supports future mis- mosphere, the Corona. She is using both namic processes at small scales in our star, ly interested in characterisation of wave of nonequilibrium and partial ionization from the interior of the Sun into the outer sions through different theoretical studies. observations (SDO, IRIS, SST) and numerical especially in active regions. For this, he pri- activity in the lower solar atmosphere, and effects in the chromosphere in magnet- solar atmosphere. She also studies the Carlos uses state-of-the-art 3D numerical simulations to study the thermodynamics marily observes using the Swedish 1-meter is one of the coordinators of the WaLSA ic flux emergence processes and related process known as reconnection. She is an simulations created with the Bifrost code of active regions. Her main research topic Solar Telescope and then uses supercom- international science team (https://WaLSA. phenomena like surges. In addition, he is observer with a big data analysis compo- to compare candidate spectral lines or to focuses on the characterisation of evapo- puters to find models that reproduce those team). Shahin is an experienced observer also interested in other eruptive/ejective nent, and uses a combination of ground- study the impact of different instrumental ration and condensations cycles in coronal observations. He is also working on the con- and passionately engages in public out- phenomena like UV bursts and coronal based and space-borne observations. She configurations on the science capabilities of loops, which are the signature of a steady nection across multiple layers in the Sun's reach activities. hot jets. His main approach is theoretical, is involved in the European Solar Telescope those missions. He also works on numerical heating mainly concentrated in the lower atmosphere via jet-like features, which through numerical experiments carried out project, participating in the Science Advi- codes that infer the physical information atmosphere of the Sun. While at RoCS, she are ever-present but difficult to observe, using the state-of-the-art Bifrost code, com- sory Group and being the EST Norwegian of the solar atmosphere when applied to lead an International Team at ISSI, Bern, especially in satellite data. Vasco has had bined with forward modeling to compare Communications officer.Ada has now start- observations. In March 2020, Carlos moved Switzerland, working on this topic. After a passion for astronomy since a teenager, with space and ground-based observations. ed a job working with big data for Expert to a position at IAC, Tenerife, Spain. 3 years in Oslo, Clara moved to Orléans, when he would bring his small telescope Analytics in Oslo but is still involved in the France in late 2019 to start a CNES post- to astronomy festivals in the Portuguese EST outreach activities. doctoral position. She is now working on countryside, and has a passion for new Solar wind observations from the Parker technologies for and beyond science. Solar Probe. 38 RoCS Annual report 2019 6 Members of the centre 39

Research Software Adjunct Principal Engineers professors Investigators

Andrius Popovas Ineke De Moortel Bart De Pontieu Mats Carlsson Boris Gudiksen Viggo Hansteen Andrius Popovas is a postdoctoral research- Ineke De Moortel is an Adjunct Professor Bart De Pontieu is an Adjunct Professor Mats Carlsson is a professor and the director Boris Gudiksen is a professor and PI at Viggo Hansteen is a senior researcher at Bay er at RoCS: numerical simulations of the at RoCS. Her research focusses on coronal at RoCS. His research is aimed at under- of RoCS. Main interests include chromo- RoCS with focus on the development of Area Environmental Research Institute as Solar atmosphere are his working horse. He heating, in particularly the efficiency of standing how the Sun’s magnetic field spheric physics and radiation MHD. He is numerical codes used to run simulations well as being a part time professor and PI is working on the next-generation simula- heating by MHD waves, using a combina- energizes the coupled solar atmosphere working with both large-scale simulations of the solar atmosphere. His main interest at RoCS. He works both on simulations and tion framework, which will use the modules tion of numerical simulations and observa- from the photosphere into the corona and and observations from the ground and from is the solar corona and how it maintains observations, from the ground and from from the Bifrost code and enable running tional data analysis. Her home institute is heliosphere. He focuses on combining high space. its high temperature. space. He is interested in how the magnetic experiments on an unprecedented scale and the University of St Andrews (UK), where resolution space- based and ground-based field is formed in the deep convection zone, complexity. This includes static and adap- she teaches Solar Theory to Mathematics multi-wavelength observations with ad- how it rises to the photosphere, and how it tive mesh refinement, multi-solver-mul- undergraduate students as well as super- vanced numerical modeling to better under- forms the outer solar atmosphere. Coronal ti-physics, etc. From March 2020, Andrius vising PhD students. stand the coupling between photosphere, heating and chromospheric dynamics and has transferred to a Research Software chromosphere and corona. He is the PI of energetics are keywords. He is the science Engineer position at RoCS. NASA’s IRIS satellite and manages the IRIS lead of the IRIS mission. research team at Lockheed Martin Solar & Astrophysics Laboratory in Palo Alto, California, USA.

Mikolaj Szydlarski Lyndsay Fletcher Juan Martínez-Sykora Tiago M. D. Pereira Luc Rouppe van der Voort Sven Wedemeyer Mikolaj Szydlarski used to be researcher Lyndsay Fletcher is Adjunct Professor at Juan Martínez-Sykora is an Adjunct As- Tiago M. D. Pereira is an associate professor Luc Rouppe van der Voort is a professor Sven Wedemeyer is an associate professor at RoCS but from January, he is working as RoCS. Her main research interest is so- sociated Professor at RoCS and based at and PI at RoCS. He studies dynamic process- and PI at RoCS. Luc’s main area of research and PI at RoCS. Sven leads the research research software engineer. Physicist and lar flares, specifically the transport of en- LMSAL and BAERI. His major contributions es in stellar atmospheres. In particular, he is high-resolution observations of the Sun. activities related to solar observations Mathematician by education, but Computer ergy through the flare atmosphere, the are on numerical modeling of the solar is working on the solar chromosphere, the He is a veteran observer at the Swedish 1-m with ALMA and supporting simulations, Scientist by heart. Mikolaj is interested in energisation of the chromosphere and the atmosphere. His main interests focus on interface between the hot corona and the Solar Telescope on the island of La Palma. which involves the ERC-funded Solar­ the application of high-performance com- interpretation of radiation signatures to chromospheric heating and dynamics and dense surface. Tiago leverages space and After years of main focus on the lower parts ALMA project, the EMISSA project (RCN), puting (HPC) to challenging problems in help us understand this process. She works multi-fluids using and developing state of ground-based observations with detailed of the solar atmosphere, he is extending his an ESO-funded development study, and solar astrophysics. His fields of expertise mostly on data analysis, figuring out ways the art 3D radiative MHD codes and com- radiative transfer calculations from 3D interest up into the transition region and the SSALMONetwork. His research most- include MHD simulations and Solar ALMA to confront data with flare models. She pare the models with ground based and models. With an interest in computational corona through coordinated observations ly focuses on the small-scale structure, data reduction. teaches students at all levels in her home space observations. astrophysics, data analysis and visualis- with the IRIS satellite. dynamics and energy balance of the solar institute (University of Glasgow, UK) and ation, he works with high-performance atmosphere with implications for other leads efforts to increase the fraction of computing and big data problems. stellar types. women and girls participating in physics and astronomy. She was a member of RoCS’ Scientific Advisory Committee until the 30th of November 2018. 40 RoCS Annual report 2019 6 Members of the centre 41

Centre Scientific Advisory Technical and administrative administration Committee associated staff

Benedikte Fagerli Karlsen Tony Arber Sarah Matthews Martina D’Angelo Terje Fredvik Stein Vidar Hagfors Haugan Benedikte Fagerli Karlsen is the centre Tony Arber is a computational plasma Sarah Matthews is a Professor of Solar Martina D’Angelo is the communication Terje Fredvik is an engineer in the insti- Stein Vidar Haugan is the technical lead coordinator at RoCS. She is responsible physicist whose interests span solar physics, Physics at UCL’s Mullard Space Science advisor and press contact at the Institute tute’s Project Related IT Services (PRITS) for the Project Related IT Services (PRITS) for the administration of the centre and space weather, laser-plasmas and QED- Laboratory. Her research interests focus on of Theoretical Astrophysics (ITA) and RoCS. group. He is the lead of the development group. He is responsible for the Hinode takes care of all practical tasks related to plasmas. He has been responsible for de- energy storage and release in magnetised Martina’s main responsibilities are internal of the data pipeline for the Solar Orbiter Science Data Centre Europe, serving data the centre’s activity. Among her tasks are veloping MHD codes for both solar physics plasmas, and in particular solar eruptive communication, creating and coordinating SPICE instrument. He is also a contributor from the Hinode and IRIS missions and new employments, visitors, contracts, re- and laser-driven fusion as well as kinetic events and space weather. Her work is outreach activities, writing popular science to the operations of the Hinode Science Data soon also data from e.g. the Solar Orbiter porting and logistics at events. codes for high-power plasma interactions. mainly observational, bringing together articles about the ongoing research and Centre Europe, a member of the ITA FITS SPICE instrument. He is a member of the For all codes, he is interested in software multi-wavelength space and ground-based news at ITA and RoCS, web editor of ITA's Working Group, and assists in the adapta- ITA FITS Working Group, acts as a liaison development methods and uncertainty observations, but she also works in collab- and RoCS' web pages and related social tion of the SOLARNET2 FITS mechanisms between RoCS and the SOLARNET2 project, quantification. oration with magnetic field modellers in media channels. for both observational and simulated data. and contributes to the data pipeline and particular to interpret the observations in quicklook software for Solar Orbiter SPICE the context of current models. She also has an interest in instrumentation and recently took on the role of Hinode EIS UK PI.

Sara Asgari Nettum Oskar Steiner Francesca Zuccarello Kristine Aa. S. Knudsen Torben Leifsen Martin Wiesmann Sara Asgari Nettum is filling Benedikte’s Oskar Steiner is a senior researcher at the Francesca Zuccarello is an associate pro- Kristine Aa. S. Knudsen is the Head of Office Torben Leifsen is the head of IT at the Martin Wiesmann is an engineer in the in- position as centre coordinator while Leibniz-Institut für Sonnenphysik (KIS) fessor at the University of Catania (Italy). at the Institute of Theoretical Astrophysics. institute. He is responsible for planning, stitute’s Project Related IT Services (PRITS) Benedikte is away on maternity leave until in Freiburg, Germany and at the Istituto Francesca is involved in the study of emer- She is the head of our administration, and building and running the IT systems to- Group. He is responsible for part of the IRIS December 2020. Ricerche Solari Locarno (IRSOL) in Swit- gence, evolution and decay of solar active cooperates closely with both the scientific, gether with the IT-group at the institute. pipeline as well as the adaptation of AIA zerland. He carries out numerical simula- regions, as well as in research related to technical and administrative staff at RoCS We are currently operating one server room and Hinode data to IRIS data. Martin also tions of the solar and stellar atmospheres, solar eruptive events. Francesca is mainly and the Institute. and will start operating a second in the contributes to the Solar Orbiter SPICE pipe- presently focussing on vortical motions and an observer. She participated in several spring of 2020 to accommodate the needs line and quicklook software. He is mainly their connection with magnetic fields. He Coordinated Observational Campaigns. of RoCS and other projects. Torben has a a programmer, implementing requests and is also interested in polarimetry and nu- background in solar physics and is a mem- wishes from various scientists into the pipe- merical methods of radiative transfer and ber of the Virgo team on the ESA spacecraft line or as separate programs. is member of RoCS’ WaLSA international SOHO, doing research in helioseismology science team. in his spare time. L. Rouppe van der Voort,L. RoCS 42 RoCS Annual report 2019 6 ChapterMembers of the centre 43

Emiriti Master students

Oddbjørn Engvold Bruce Arnold Chappell Ida Risnes Hansen Oddbjørn Engvold is an emeritus profes- Bruce is a first-year masters student in the Ida Risnes Hansen is a Master's student sor at RoCS. One of his main areas of re- Computational Science department and at RoCS. She joined Tiago M.D. Pereira’s search is structure and dynamics of solar writing his thesis with the solar group at project on Monte Carlo radiative trans- prominences. He is a veteran user of the ITA. He is coming from a physics bachelors fer methods in stellar atmospheres. Ida is Swedish 1-m Solar Telescope on the island background from the US and his academic interested in the history of discoveries in of La Palma and of solar telescopes of the interests are machine learning, data ana­ astronomy, and the lives of the scientists US National Solar Observatory (NSO). He lysis, and high performance computing. behind them. has in recent years edited and contributed The general plan for his thesis is to use to two books related to solar activity. machine learning methods applied to 3D spectral synthesis.

Rob Rutten Ingrid Marie Kjelseth Mats Ola Sand Rob Rutten is an emeritus adjunct professor Ingrid Marie Kjelseth is a master's student Mats Ola Sand is a master’s student at RoCS. at RoCS. He is a world leading expert in at RoCS. Ingrid's research involves main- Mats Ola's research is focusing on detect- radiative transfer and spectral diagnostics. ly the solar radiation, looking at both its ing the full extent of spicules in the Ca II His lecture notes are used in teaching ra- magnetic field dependency and how it af- spectral images from the new CHROMIS diative transfer all over the world. fects the Earth climate. She has taken part instrument at the Swedish 1-m Solar Tel- in observations and use data from both escope (SST). He will start his thesis under SST, ALMA and IRIS for studying different supervision by Tiago M. D. Pereira in the spectral lines and improving today's solar autumn of 2020. He is also a representative irradiance models. for the students at the institute board. 44 RoCS Annual report 2019 7 Appendices 45

Froment, Clara; Antolin, Patrick; Henri- Hansteen, Viggo. Ellerman bombs and UV Jafarzadeh, Shahin; Wedemeyer, Sven; Talks and presentations ques, Vasco; Kohutova, Petra; van der bursts in the solar chromosphere. Nor- Noda, Carlos Quintero; Wiegelmann, Voort, Luc H.M. Rouppe. Multi-scale dita Conference on Helicity in the Solar Thomas; Rouppe van der Voort, Luc. observations of thermal nonequilibrium Atmosphere; 2019-03-04 - 2019-03-08 Magnetic-field topology throughout the cycles in coronal loops. Coronal Loops solar chromosphere. NLTE inversion 2019 Workshop 9; 2019-06-10 - 2019-06-13 Workshop; 2019-12-15 - 2019-12-18 Hansteen, Viggo. Ellerman Bombs and UV bursts, numerical simulations and IRIS – Froment, Clara; Antolin, Patrick; Henri- observations. Hinode 13; 2019-09-02 - Jafarzadeh, Shahin; Wedemeyer, Sven; ques, Vasco; Kohutova, Petra; van der 2019-09-06 Szydlarski, Mikolaj Marcin. Temperature Voort, Luc Rouppe. Multi-scale observa- Fluctuations in the Solar Chromosphere tions of thermal nonequilibrium cycles with ALMA. AOGS 2019; 2019-07-28 - in coronal loops (presenting author: Pat- Hansteen, Viggo. Ellerman Bombs and UV 2019-08-02 rick Antolin). National Astronomy Meet- bursts, reconnection at different heights Bose, Souvik. Expanding the Capabilities Carlsson, Mats. Numerical simulations of Fletcher, Lyndsay. Multi-wavelength ing (NAM); 2019-06-30 - 2019-07-04 in the chromosphere?. IAUS 354; 2019- of NASA's Solar Dynamics Observatory. the chromosphere. ISSI team 399 work- Observations of Solar Flares. 2nd China- 07-01 - 2019-07-05 Jafarzadeh, Shahin; Wedemeyer, Sven; NASA Frontier Development Lab Event shop "Studying Magnetic-Field-Regulat- Europe Solar Physics Meeting (CESPM Szydlarski, Mikolaj Marcin; Fleck, Bern- Finale; 2019-08-16 - 2019-08-17 ed Heating in the Solar Chromosphere"; 2019); 2019-05-06 - 2019-05-10 Guevara Gomez, Juan Camilo; Martinez hard. Wave heating of the lower solar 2019-11-18 - 2019-11-21 Oliveros, Juan Carlos; Krucker, S; Hudson, Hansteen, Viggo. Ellerman Bombs and atmosphere. Hinode-13/IPELS 2019; Hugh; Buitrago Casas, Juan Camilo. UV-bursts, a result of flux emergence. 2019-09-02 - 2019-09-06 Bose, Souvik. How might we expand the Fletcher, Lyndsay. Solar Flares - obser- On the observation of a classical Flux Emergence Workshop series; 2019- capabilities of NASA’s Solar Dynamics Carlsson, Mats. RoCS. Birkeland Centre vational gaps and priorities. Preparing loop-prominence system during the 2017 03-18 - 2019-03-22 Observatory using Machine Learning?. for Space Science retreat; 2019-03-05 - for the next generation of ground-based September 10 flare. HINODE 13 / IPELS Jafarzadeh, Shahin; Wedemeyer, Sven; NASA Frontier Development Lab Event 2019-03-05 solar physics observations; 2019-07-23 - 2019; 2019-09-02 - 2019-09- 06 Szydlarski, Mikolaj Marcin; Fleck, Finale; 2019-08-16 - 2019-08-17 2019-07-25 Hansteen, Viggo. Ellerman Bombs and Bernhard; Stangalini, Marco. Wave UV-bursts, a result of flux emergence. heating of the solar chromosphere from Carlsson, Mats. Solar storms: Wildest Guevara Gomez, Juan Camilo; Wedemey- Flux Emergence Workshop series; 2019- observations with ALMA. ALMA-2019: Bose, Souvik; Henriques, Vasco; Joshi, weather in the solar system. Njord Fletcher, Lyndsay. Solar Flares and Erup- er, Sven; Jafarzadeh, Shahin; Szydlarski, 03-18 - 2019-03-22 Science Results and Cross-Facility Jayant; Rouppe van der Voort, L. H. M.. Christmas Seminar; 2019-12-02 - 2019- tions. The 27th IUGG General Assembly; Mikolaj Marcin. Dynamics of solar iso- Synergies; 2019-10-14 - 2019-10-18 Characterization and formation of Ca II 12-02 2019-06-08 - 2019-08-18 lated features observed by the Atacama K and Mg II k spectra of spicules. IRIS 10; Large Millimeter/submillimeter Array Hansteen, Viggo. The FIP effect in the 2019-11-04 - 2019-11-08 (ALMA). HINODE 13 / IPELS 2019; 2019- Chromosphere, Transition Region, Coro- Joshi, Jayant. Properties of Chromospheric Carlsson, Mats. The F-CHROMA grid of Fletcher, Lyndsay. Will we all fry in the 09- 02 - 2019-09-06 na, and Solar Wind. ISSI meeting Bern; Magnetic Field of Sunpots. Invited 1D RADYN flare models. RoCS gathering; next solar storm?. Glasgow Skeptics; 2019-02-11 - 2019-02-14 seminar; 2019-01-10 - 2019-01-10 Carlsson, Mats. Bifrost. WholeSun kickoff 2019-11-28 - 2019-11-29 2019-06-24 meeting; 2019-05-27 - 2019-05-29 Guevara Gomez, Juan Camilo; Wedemey- er, Sven; Jafarzadeh, Shahin; Szydlarski, Jafarzadeh, Shahin. Joshi, Jayant. Spectro-polarimetry of two Carlsson, Mats. WP4 Heating and ther- Fredvik, Terje. Oslo SPICE Status. SPICE Mikolaj Marcin. Structure and dynamics Learning physics with our living star, B-class flares in the Ca II 8542 A line. Carlsson, Mats. Bruk av IT i solforskning. mo-dynamical coupling of the solar Consortium Meeting 4; 2019-05-14 - of isolated features in the solar chro- the Sun. Faglig-pedagogisk dag; 2019-10- IRIS 10; 2019-11-04 - 2019-11-08 IT-konferansen 2019; 2019-06-03 - 2019- atmosphere, Energy budget. WholeSun 2019-05-15 mosphere observed with ALMA. 2nd 31 - 2019-10-31 06-03 kickoff meeting; 2019-05-27 - 2019-11-29 China-Europe Solar Physics Meeting (CESPM 2019); 2019-05-06 - 2019-05-10 Kohutova, Petra. Probing the nature Fredvik, Terje. Oslo SPICE Status. SPICE Jafarzadeh, Shahin; van der Voort, Luc of coronal heating through thermal Carlsson, Mats. Innovation in Solar Phys- de Jorge Henriques, Vasco Manuel; Rouppe Consortium Meeting 5; 2019-11-19 - 2019- H.M. Rouppe; Wedemeyer, Sven; Noda, instability and coronal rain. Institute ics Research. Birkelandforelesningen van der Voort, Luc. Unifying umbral 11-20 Hansteen, Viggo. EBs and UV-bursts: Carlos Quintero. Magnetic-field topology colloquium; 2019-11-07 - 2019-11-07 2019; 2019-09-24 - 2019-09-24 chromospheric dynamics at small scales. reconnection at different heights in the of fibrillar structures throughout the IRIS-10; 2019-11-04 - 2019-11-08 solar atmosphere. AGU; 2019-12-09 - solar chromosphere. Solar Polarization Fredvik, Terje. Quicklook and Analysis 2019-12-12 Workshop 9; 2019-08-26 - 2019-08-30 Kohutova, Petra. Waves in the solar Carlsson, Mats. New Bifrost models. Tools. SPICE Consortium Meeting 4; atmosphere and MHD seismology. WALSA workshop; 2019-08-12 - 2019- Eklund, Henrik; Szydlarski, Mikolaj 2019-05-14 - 2019-05-15 Institute colloquium; 2019-03-29 - 2019- 08-16 Marcin; Wedemeyer, Sven. Shock wave Hansteen, Viggo. Ellerman Bombs and UV Jafarzadeh, Shahin; Wedemeyer, Sven. 03-29 propagation with high cadence solar bursts - observations. IRIS 10; 2019-11-04 Observing Waves in the Lower Solar ALMA time series. Hinode-13/IPELS 2019; Froment, Clara. Le système solaire. - 2019-11-08 Atmosphere with ALMA. Preparing for Carlsson, Mats. New 3D models of the 2019-09-02 - 2019-09-06 Presentation at the French School in Oslo the next generation of ground-based Kohutova, Petra; Antolin, Patrick; chromosphere and TR. CLASP2 Science - for elementary school students; 2019- solar physics observations; 2019-07-23 - Popovas, Andrius; Szydlarski, Mikolaj Meeting; 2019-11-12 - 2019-11-13 03-07 - 2019-03-07 2019-07-26 Marcin; Hansteen, Viggo. 3D radiative Fletcher, Lyndsay. Energy Transport and MHD simulations of coronal rain forma- Dissipation in Solar Flares. Seminar; tion and evolution. Hinode 13; 2019-09- 2019-03-12 - 2019-03-12 02 - 2019-09-06 46 RoCS Annual report 2019 7 Appendices 47

Papers in refereed journals 2019 –

Kohutova, Petra; Verwichte, Erwin; Nóbrega Siverio, Daniel Elias. Nonequilib- Wedemeyer, Sven. High-cadence imaging Al-Janabi, K., Antolin, P., Baker, D., Bellot Carlsson, M., De Pontieu, B., & Hansteen, Esteban Pozuelo, S., de la Cruz Froment, Clara. Propagating torsional rium ionization effects in magnetic flux of the Sun. ALMA Development Work- Rubio, L. R., Bradley, L., Brooks, D. H., V. H.:2019, Annual Review of Astronomy Rodríguez, J., Drews, A., Rouppe van oscillation of a chromospheric surge. 9th emergence processes. Flux Emergence shop; 2019-06-03 - 2019-06-05 Centeno, R., Culhane, J. L., Del Zanna, G., and Astrophysics 57, 189, New View of der Voort, L., Scharmer, G. B., & Carlsson, Coronal Loops Workshop; 2019-06-11 - Workshop (FEW 2019); 2019-03-18 - Doschek, G. A., Fletcher, L., et al.:2019, the Solar Chromosphere M.:2019, The Astrophysical Journal 870, 2019-06-14 2019-03-22 Publications of the Astronomical Society 88, Observationally Based Models of Wedemeyer, Sven. High-tech and llamas. of Japan 71, R1, Achievements of Hinode Penumbral Microjets Astromomy on Tap; 2019-06-24 - 2019- in the first eleven years Cheung, M. C. M., Rempel, M., Martinez-Sykora, Juan. Beyond single fluid Nóbrega Siverio, Daniel Elias. Surges: 06-24 Chintzoglou, G., Chen, F., Testa, P., or two fluids: Multi-component (multi- a missing piece in the solar atmosphere Martínez-Sykora, J., Sainz Dalda, A., Freudenthal, J.; von Essen, C.; Ofir, A.; species) and multi fluid effects in the puzzle. Whole Sun kick-off meeting; Armstrong, J. A., & Fletcher, L.:2019, DeRosa, M. L., Malanushenko, A., Dreizler, S.; Agol, E.; Wedemeyer, S., et solar atmosphere. ISSI meeting: Studying 2019-05-27 - 2019-05-29 Wedemeyer, Sven. Magnetic Field Meas- Solar Physics 294, 80, Fast Solar Image Hansteen, V., De Pontieu, B., Carlsson, al.:2019, Astronomy and Astrophysics Magnetic-Field-Regulated Heating in the urements with the Atacama Millimeter/ Classification Using Deep Learning and M., Gudiksen, B., & McIntosh, S. W.:2019, 628, A108, Kepler Object of Interest Net- Solar Chromosphere; 2019-11-18 - 2019- submillimeter Array. IAU Symposium Its Importance for Automation in Solar Nature Astronomy 3, 160, A comprehen- work. III. Kepler-82f: a new non-transit- 11-21 Nóbrega Siverio, Daniel Elias. Unrave- 354 - Solar and Stellar Magnetic Fields: Physics sive three-dimensional radiative mag- ing 21 M⊕ planet from photodynamical ling the heating in the chromosphere: Origins and Manifestations; 2019-07-01 - netohydrodynamic simulation of a solar modelling nonequilibrium and partial ionization 2019-07-05 flare Martinez-Sykora, Juan. Ebysus: a multi- effects. Whole Sun kick-off meeting; Bai, X., Socas-Navarro, H., Nóbrega- fluid and multi-species numerical code: on 2019-05-27 - 2019-05-29 Siverio, D., Su, J., Deng, Y., Li, D., Cao, W., Froment, C., Antolin, P., Henriques, V. M. coupling between ionized species. AGU Wedemeyer, Sven. & Ji, K.:2019, The Astrophysical Journal Cheung, M. C. M., De Pontieu, B., Martín- J., Kohutova, P., & Rouppe van der Voort, Fall meeting; 2019-12-09 - 2019-12-13 Magnetic Tornadoes on the Sun. ISSI 870, 90, Signatures of Magnetic Recon- ez-Sykora, J., Testa, P., Winebarger, A. L. H. M.:2019, Astronomy and Astrophys- Ortiz, Ada. A tour to the Sun: so close, International Team 449 - The nature and nection at the Footpoints of Fan-shaped R., Daw, A., Hansteen, V., Antolin, P., ics 633, A11, Multi-scale observations so mysterious. Apen Dag 2019; 2019-03- physics of vortex flows in solar plasmas; Jets on a Light Bridge Driven by Photo- Tarbell, T. D., Wuelser, J.-P., Young, P., of thermal non-equilibrium cycles in Martinez-Sykora, Juan. Ebysus: Multi- 07 - 2019-03-07 2019-02-04 - 2019-02-04 spheric Convective Motions & MUSE Team:2019, The Astrophysical coronal loops fluid & multi-species numerical code. Journal 882, 13, Multi-component De- Partially Ionised Plasmas in Astrophysics composition of Astronomical Spectra by — PIPA2019; 2019-06-03 - 2019-06-07 Ortiz, Ada. Hidden figures: amazing Wedemeyer, Sven. Bergemann, M., Gallagher, A. J., Eitner, Compressed Sensing Graham, D. R., De Pontieu, B., & Testa, women astronomers and their legacy. Our Dynamic Sun. Seminar ved IFT UiB; P., Bautista, M., Collet, R., Yakovleva, S. P.:2019, The Astrophysical Journal 880, Astronomy on Tap; 2019-02-25 - 2019- 2019-10-15 - 2019-10-15 A., Mayriedl, A., Plez, B., Carlsson, M., L12, Automated Detection of Rapid Var- Nóbrega Siverio, Daniel Elias. An updated 02-25 Leenaarts, J., Belyaev, A. K., & Hansen, Chitta, L. P., Sukarmadji, A. R. C., Rouppe iability of Moss Using SDO/AIA and Its vision of solar surges. 2nd China-Europe C.:2019, Astronomy and Astrophysics van der Voort, L., & Peter, H.:2019, Connection to the Solar Corona Solar Physics Meeting (CESPM 2019); Wedemeyer, Sven. 631, A80, Observational constraints on Astronomy and Astrophysics 623, A176, 2019-05-06 - 2019-05-10 Rouppe van der Voort, Luc. Penumbral Solar Astronomy with ALMA. the origin of the elements. I. 3D NLTE Energetics of magnetic transients in a micro-jets at high spatial and temporal ALMA2019: Science Results and formation of Mn lines in late-type stars solar active region plage Hansteen, V., Ortiz, A., Archontis, V., resolution. IRIS-10 meeting; 2019-11-04 - Cross-Facility Synergies; 2019-10-14 - Carlsson, M., Pereira, T. M. D., & Bjørgen, Nóbrega Siverio, Daniel Elias. Modeling 2019-11-08 2019-10-18 J. P.:2019, Astronomy and Astrophys- UV bursts. IRIS 10; 2019-11-04 - 2019-11- Bose, S., Henriques, V. M. J., Rouppe van De Pontieu, B., Martínez-Sykora, J., Testa, ics 626, A33, Ellerman bombs and UV 08 der Voort, L., & Pereira, T. M. D.:2019, P., Winebarger, A. R., Daw, A., Hansteen, bursts: transient events in chromospher- Rouppe van der Voort, Luc. Penumbral Wedemeyer, Sven. Astronomy and Astrophysics 627, A46, V., Cheung, M. C. M., & Antolin, P.:2019, ic current sheets micro-jets at high spatial and tempo- Solar science with ALMA in Norway. Semi-empirical model atmospheres for The Astrophysical Journal 888, 3, The Nóbrega Siverio, Daniel Elias. Nonequilib- ral resolution. ISSI team 399 workshop Norwegian ALMA Day 2019; 2019-04-04 the chromosphere of the sunspot pe- Multi-slit Approach to Coronal Spectros- rium ionization and ambipolar diffusion "Studying Magnetic-Field-Regulated - 2019-04-04 numbra and umbral flashes copy with the Multi-slit Solar Explorer Hong, J., Li, Y., Ding, M. D., & Carlsson, in magnetic flux emergence processes. Heating in the Solar Chromosphere"; (MUSE) M.:2019, The Astrophysical Journal 879, Partially Ionised Plasmas in Astrophysics 2019-11-18 - 2019-11-21 128, The Response of the Lyα Line in (PIPA2019); 2019-06-03 - 2019-06-07 Bose, S., Henriques, V. M. J., Joshi, J., & Different Flare Heating Models

Rouppe van der Voort, L.:2019, Astrono- Engvold, O:2019, Proceedings of the my and Astrophysics 631, L5, Characteri- International Astronomical Union 13, 75, zation and formation of on-disk spicules IAU’s Interaction with Young As- trono- in the Ca II K and Mg II k spectral lines mers 48 RoCS Annual report 2019 7 Appendices 49

Howson, T. A., De Moortel, I., Reid, J., & Kasparova, J., Carlsson, M., Varady, Kowalski, A. F., Butler, E., Daw, A. N., Pagano, P., & De Moortel, I.:2019, Astron- Rodger, A. S., Labrosse, N., Wedemey- Vissers, G. J. M., de la Cruz Rodríguez, J., Hood, A. W.:2019, Astronomy and As- M., Heinzel, P.: 2019, ASP Conference Fletcher, L., Allred, J. C., De Pontieu, omy and Astrophysics 623, A37, Con- er, S., Szydlarski, M., Simões, P. J. A., & Libbrecht, T., Rouppe van der Voort, L. H. trophysics 629, A60, Magnetohydro- dy- Series ,141, Modelling of Flare Processes: B., Kerr, G. S., & Cauzzi, G.:2019, The tribution of observed multi frequency Fletcher, L.:2019, The Astrophysical Jour- M., Scharmer, G. B., & Carlsson, M.:2019, namic waves in braided magnetic fields A Comparison of the Two RHD Codes Astrophysical Journal 878, 135, Spectral spectrum of Alfv ́en waves to coronal nal 875, 163, First Spectral Analysis of a Astronomy and Astrophysics 627, A101, FLARIX and RADYN Evidence for Heating at Large Column heating Solar Plasma Eruption Using ALMA Dissecting bombs and bursts: non-LTE Mass in Umbral Solar Flare Kernels. I. inversions of low-atmosphere reconnec- Howson, T. A., De Moortel, I., Antolin, IRIS Near-UV Spectra of the X1 Solar tion in SST and IRIS observations P., Van Doorsselaere, T., & Wright, A. Kerr, G. S., Carlsson, M., Allred, J. C., Flare of 2014 October 25 Panesar, N. K., Sterling, A. C., Moore, Rouppe van der Voort, L. H. M., & Drews, N.:2019, Astronomy and Astrophys- Young, P. R., & Daw, A. N.:2019, The R. L., Winebarger, A. R., Tiwari, S. 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"Even after all this time The Sun never says to the Earth,

‘You owe me.’

Look what happens with a love like that, It lights the whole sky."

Hafez

D. Nobrega Siverio, RoCS 52 NCMM Annual Report 2017

mn.uio.no/rocs