DOCSLIB.ORG

AGU 2018 Mishin-Streltsov.Pdf Eposter

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
AGU 2018 Mishin-Streltsov.Pdf Eposter Turbulent Plasmasphere Boundary Layer Evgeny Mishin* and Anatoly Streltsov** *Space Vehicles Directorate **Embry- Riddle Aeronautical University Paper # SA41C- 3495DISTRIBUTION STATEMENT A – Unclassified, Unlimited Distribution ABSTRACT • Observations of plasma turbulence and heated/accelerated plasma particles in the plasmasphere boundary layer formed by reconnection- injected mesoscale hot plasma flows (MPFs) penetrating into the plasmasphere are presented. • Free energy comes from the electron diamagnetic current in the entry layer near the plasma sheet boundary, diamagnetic ion current near the inner boundary of the layer, and anisotropic (sometimes ring-like) ion distributions inside, and further inward of, the inner boundary. • Collisionless heating of the plasmaspheric particles gives downward heat and suprathermal electron fluxes sufficient to provide the F-region electron temperature greater than 6000 K. This leads to the formation of specific density troughs in the ionospheric regions in the absence of strong electric fields and upward plasma flows. • Small-scale MHD wave structures (SAPSWS) and irregular density troughs emerge on the duskside, coincident with the substorm current wedge development. Numerical simulations show that the ionospheric feedback instability significantly contributes to the SAPSWS formation. Mishin, E. (2013), Interaction of substorm injections with the subauroral geospace: 1. Multispacecraft observations of SAID, J. Geophys. Res. Space Physics, 118, 10.1002/jgra.50548. Mishin, E., Y. Nishimura, and J. Foster (2017), SAPS/SAID revisited: A causal relation to the substorm current wedge, J. Geophys. Res. Space Physics, 122, doi:10.1002/2017JA024263. Mishin, E., and V. Sotnikov (2017), The turbulent plasmasphere boundary layer and the outer radiation belt boundary, Plasma Phys. Control. Fusion, 59, 124003, doi:10.1088/1361-6587/aa8481. Streltsov, A., & Mishin, E. (2018). Ultralow frequency electrodynamics of magnetosphere-ionosphere interactions near the plasmapause during substorms. J. Geophys. Res.: Space Physics, 123. The plasmasphere boundary layer: A power plant in the magnetosphere CRRES, Polar, Cluster, and Van Allen Probes observations strongly suggest that the plasmapause serves as a power plant in the magnetosphere converting kinetic energy of the magnetotail mesoscale plasma flows (MPFs) into the large-scale electric field. Schematic of the energy conversion on the plasmapause Substorm Injections: Mesoscale (∆Y< 3RE) Plasma Flows (MPFs) Magnetotail reconnection: The region around the X-line Low-β jets of a finite width, ∆Y, moving across a magnetic barrier B(x)||Z , maintain motion with the bulk speed v0||X due to the polarization field EY=-v0xB, which builds up in the front (numerous laboratory experiments). Kinetic energy Electric energy Short Circuiting over the Plasmapause The polarization field builds up if the ambient plasma is unable to neutralize the polarization charge at the front. When the cold plasma density at the plasmapause exceeds ~5-10 cm-3, the polarization field is shorted out, so that the MPF’s electrons are arrested and the abrupt, dispersionless Plasma Sheet (auroral) boundary is formed. The MPF’s (hot) ions continue moving into the plasmasphere devoid of the hot electrons. Charge neutrality is supported by the cold plasma. The subauroral electric field emerges to support the short-circuit current system in the plasmasphere. Enhanced plasma turbulence provides anomalous circuit resistivity and magnetic diffusion. Short Circuiting Short circuiting occurs at nambient > nc = nMPF/Ac [Rozhanskii, 1986] El. `collision’ width frequency In the plasmasphere, ‘collisions’ are due to wave-particle interactions To match the -3-3.5 observations ν ≅ 10 ωpe ≅ ωLHR Short-Circuiting Observations Ion de-magnetization εmin (η) ≅e∆Φ (η) penetration of unmagnetized ions through a potential barrier η SAID system of reference η n0 = nc at η=0 De-magnetization of hot ions and prompt magnetic diffusion, as in plasmoid-magnetic barrier experiments [Mishin et al., 1986; Brenning et al., 2005]. orbit chaotization Mishin, 2013 Entry Layer . As the hot plasma inflow continues, the hot electrons accumulate near the PS boundary creating the electron pressure peak. In a steady state, the Pressure hot electron pressure peak buildup is balanced by the diamagnetic drift resulting in tens nA/m2 azimuthal currents excitation of lower hybrid, fast magnetosonic, and EMIC waves in the entry layer. Entry Layer (cont) . Diamagnetic lower hybrid drift instability results in the anomalous collision frequency LHR 10fci Sotnikov et al., 1980 The r.m.s. amplitude in ν ≅ω the entry layer e LHR 0.7 mV/m . Heating and acceleration of the plasmasphere’s particles The “hot zone” near the plasmapause The “hot zone” in the ionosphere A scenario of subauroral ionospheric heating due to wave-particle Ionospheric structures during the SAID events interactions in the TPBL on (A) 8 April 2004 and (B) 18 March 2002 and 17 March 2013. Alfvénic features near the plasmapause RBSP-A observations of small-scale Alfvénic features near the plasmapause during the St. Patrick’s day 2015 major storm (03/17/2015 event). Mishin, E., Nishimura, Y. & Foster, J. (2017). SAPS/SAID revisited: A causal relation to the substorm current wedge. J. Geophys. Res.: Space Physics, 122. Two-Fluid MHD Modeling A two-fluid MHD model describes the positive ionospheric feedback instability driven by the large- scale electric field Summary Short-circuiting of reconnection-injected mesoscale plasma flows over the plasmapause results in formation of the turbulent plasmaspheric boundary layer (TPBL) and enhanced subauroral electric fields. The plasmapause serves as a power plant in the magnetosphere converting kinetic energy of the mesoscale plasma flows into the large- scale electric field. Enhanced plasma turbulence provides anomalous circuit resistivity and magnetic diffusion, as well as heating and acceleration of cold plasma particles..
Load more

Recommended publications
  • Ejecta Event Associated with a Two&Hyphen;Step Geomagnetic Storm
    JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 111, A11104, doi:10.1029/2006JA011893, 2006 A two-ejecta event associated with a two-step geomagnetic storm C. J. Farrugia,1 V. K. Jordanova,1,2 M. F. Thomsen,2 G. Lu,3 S. W. H. Cowley,4 and K. W. Ogilvie5 Received 2 June 2006; revised 1 September 2006; accepted 12 September 2006; published 16 November 2006. [1] A new view on how large disturbances in the magnetosphere may be prolonged and intensified further emerges from a recently discovered interplanetary process: the collision/merger of interplanetary (IP) coronal mass ejections (ICMEs; ejecta) within 1 AU. As shown in a recent pilot study, the merging process changes IP parameters dramatically with respect to values in isolated ejecta. The resulting geoeffects of the coalesced (‘‘complex’’) ejecta reflect a superposition of IP triggers which may result in, for example, two-step, major geomagnetic storms. In a case study, we isolate the effects on ring current enhancement when two coalescing ejecta reached Earth on 31 March 2001. The magnetosphere ‘‘senses’’ the presence of the two ejecta and responds with a reactivation of the ring current soon after it started to recover from the passage of the first ejection, giving rise to a double-dip (DD) great storm (each min Dst < À250 nT). A drift-loss global kinetic model of ring current buildup shows that in this case the major factor determining the intensity of the storm activity is the very high (up to 10 cmÀ3) plasma sheet density. The plasma sheet density, in turn, is found to correlate well with the very high solar wind density, suggesting the compression of the leading ejecta as the source of the hot, superdense plasma sheet in this case.
    [Show full text]
  • Mechanisms of Formation of Multiple Current Sheets in the Heliospheric Plasma Sheet
    EGU2020-3945 https://doi.org/10.5194/egusphere-egu2020-3945 EGU General Assembly 2020 © Author(s) 2021. This work is distributed under the Creative Commons Attribution 4.0 License. Mechanisms of formation of multiple current sheets in the heliospheric plasma sheet Evgeniy Maiewski1, Helmi Malova2,3, Roman Kislov3,4, Victor Popov5, Anatoly Petrukovich3, and Lev Zelenyi3 1National Research University”Higher School of Economics”, Moscow, Russian Federation ([email protected]) 2Scobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow, Russia ([email protected]) 3Space Research Institute of the Russian Academy of Science, Moscow, Russia 4Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation of the Russian Academy of Sciences (IZMIRAN), Moscow, Russia 5Faculty of Physics, Lomonosov Moscow State University, Moscow, Russia When spacecraft cross the heliospheric plasma sheet (HPS) that separates large-scale magnetic sectors of the opposite direction in the solar wind, multiple rapid fluctuations of a sign of the radial magnetic field component are observed very often, indicating the presence of multiple current sheets occurring within the HPS. Possible mechanisms of formation of these structures in the solar wind are proposed. Taking into accout that the streamer belt in the solar corona is believed to be the main source of the slow solar wind in the heliosphere, we suggest that the effect of the multi-layered HPS is determined by the extension of many streamer-belt-borne thin current sheets oriented along the neutral line of the interplanetary magnetic field. Within the framework of a proposed MHD model, self-consistent distributions of the key solar wind characteristics which depend on streamer propreties are investigated.
    [Show full text]
  • Solar Wind Properties and Geospace Impact of Coronal Mass Ejection-Driven Sheath Regions: Variation and Driver Dependence E
    Solar Wind Properties and Geospace Impact of Coronal Mass Ejection-Driven Sheath Regions: Variation and Driver Dependence E. K. J. Kilpua, D. Fontaine, C. Moissard, M. Ala-lahti, E. Palmerio, E. Yordanova, S. Good, M. M. H. Kalliokoski, E. Lumme, A. Osmane, et al. To cite this version: E. K. J. Kilpua, D. Fontaine, C. Moissard, M. Ala-lahti, E. Palmerio, et al.. Solar Wind Properties and Geospace Impact of Coronal Mass Ejection-Driven Sheath Regions: Variation and Driver Dependence. Space Weather: The International Journal of Research and Applications, American Geophysical Union (AGU), 2019, 17 (8), pp.1257-1280. 10.1029/2019SW002217. hal-03087107 HAL Id: hal-03087107 https://hal.archives-ouvertes.fr/hal-03087107 Submitted on 23 Dec 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. RESEARCH ARTICLE Solar Wind Properties and Geospace Impact of Coronal 10.1029/2019SW002217 Mass Ejection-Driven Sheath Regions: Variation and Key Points: Driver Dependence • Variation of interplanetary properties and geoeffectiveness of CME-driven sheaths and their dependence on the E. K. J. Kilpua1 , D. Fontaine2 , C. Moissard2 , M. Ala-Lahti1 , E. Palmerio1 , ejecta properties are determined E.
    [Show full text]
  • The Magnetosphere-Ionosphere Observatory (MIO)
    1 The Magnetosphere-Ionosphere Observatory (MIO) …a mission concept to answer the question “What Drives Auroral Arcs” ♥ Get inside the aurora in the magnetosphere ♥ Know you’re inside the aurora ♥ Measure critical gradients writeup by: Joe Borovsky Los Alamos National Laboratory [email protected] (505)667-8368 updated April 4, 2002 Abstract: The MIO mission concept involves a tight swarm of satellites in geosynchronous orbit that are magnetically connected to a ground-based observatory, with a satellite-based electron beam establishing the precise connection to the ionosphere. The aspect of this mission that enables it to solve the outstanding auroral problem is “being in the right place at the right time – and knowing it”. Each of the many auroral-arc-generator mechanisms that have been hypothesized has a characteristic gradient in the magnetosphere as its fingerprint. The MIO mission is focused on (1) getting inside the auroral generator in the magnetosphere, (2) knowing you are inside, and (3) measuring critical gradients inside the generator. The decisive gradient measurements are performed in the magnetosphere with satellite separations of 100’s of km. The magnetic footpoint of the swarm is marked in the ionosphere with an electron gun firing into the loss cone from one satellite. The beamspot is detected from the ground optically and/or by HF radar, and ground-based auroral imagers and radar provide the auroral context of the satellite swarm. With the satellites in geosynchronous orbit, a single ground observatory can spot the beam image and monitor the aurora, with full-time conjunctions between the satellites and the aurora.
    [Show full text]
  • Dust Clouds and Plasmoids in Saturn's Magnetosphere
    Dust clouds and plasmoids in Saturn’s Magnetosphere as seen with four Cassini instruments Emil Khalisi1 Max-Planck-Institute for Nuclear Physics, Saupfercheckweg 1, D–69117 Heidelberg, Germany Abstract We revisit the evidence for a ”dust cloud” observed by the Cassini space- craft at Saturn in 2006. The data of four instruments are simultaneously compared to interpret the signatures of a coherent swarm of dust that would have remained near the equatorial plane for as long as six weeks. The con- spicuous pattern, as seen in the dust counters of the Cosmic Dust Analyser (CDA), clearly repeats on three consecutive revolutions of the spacecraft. That particular cloud is estimated to about 1.36 Saturnian radii in size, and probably broadening. We also present a reconnection event from the magnetic field data (MAG) that leave behind several plasmoids like those reported from the Voyager flybys in the early 1980s. That magnetic bubbles happened at the dawn side of Saturn’s magnetosphere. At their nascency, the magnetic field showed a switchover of its alignment, disruption of flux tubes and a recovery on a time scale of about 30 days. However, we cannot rule out that different events might have taken place. Empirical evidence is shown at another occasion when a plasmoid was carrying a cloud of tiny dust particles such that a connection between plasmoids and coherent dust clouds is probable. Keywords: Dust clouds, Saturn, Cassini mission, Cosmic Dust Analyser, arXiv:1702.01579v1 [astro-ph.EP] 6 Feb 2017 Magnetosphere URL: DOI: http://dx.doi.org/10.1016/j.asr.2016.12.030 (Emil Khalisi) 1Corresponding author: [email protected] Preprint accepted by Advances in Space Research [JASR13029] 7th February 2017 1.
    [Show full text]
  • Cold and Dense Plasma Sheet Caused by Solar Wind Entry: Direct Evidence
    atmosphere Case Report Cold and Dense Plasma Sheet Caused by Solar Wind Entry: Direct Evidence Yue Yu 1,2, Zuzheng Chen 1,2,* and Fang Chen 1,2 1 School of Space and Environment, Beihang University, Beijing 100089, China; [email protected] (Y.Y.); [email protected] (F.C.) 2 Key Laboratory of Space Environment Monitoring and Information Processing, Ministry of Industry and Information Technology, Beijing 100089, China * Correspondence: [email protected] Received: 12 June 2020; Accepted: 2 August 2020; Published: 7 August 2020 Abstract: We present a coordinated observation with the Magnetospheric Multiscale (MMS) mission, located in the Earth’s magnetotail plasma sheet, and the Acceleration, Reconnection, Turbulence, and Electrodynamics of the Moon’s Interaction with the Sun (ARTEMIS) mission, located in the solar wind, in order to understand the formation mechanism of the cold and dense plasma sheet (CDPS). MMS detected two CDPSs composed of two ion populations with different energies, where the energy of the cold ion population is the same as that of the solar wind measured by ARTEMIS. This feature directly indicates that the CDPSs are caused by the solar wind entry. In addition, He+ was observed 3 3 in the CDPSs. The plasma density in these two CDPSs are ~1.8 cm− and ~10 cm− , respectively, roughly 4–30 times the average value of a plasma sheet. We performed a cross-correlation analysis on the ion density of the CDPS and the solar wind, and we found that it takes 3.7–5.9 h for the solar wind to enter the plasma sheet.
    [Show full text]
  • 3 the Magnetosphere 3-1 Formation of the Magnetosphere and Magnetospheric Plasma Regime
    3 The Magnetosphere 3-1 Formation of the Magnetosphere and Magnetospheric Plasma Regime OBARA Takahiro The Earth's magnetosphere is formed by the plasma flow from the Sun; i.e. solar wind. This solar wind particle can enter the magnetosphere through non-MHD processes and pro- duces specific regions of plasma. This is due to the convection motion seen in the magne- tosphere. An enhancement of the magnetospheric convection causes storms and sub- storms in the magnetosphere. Highly energetic particles can be produced through very effi- cient acceleration processes during the storms. In this paper we describe the fundamental physics of the magnetosphere, aiming a transition of researches to the Space Weather fore- cast. Keywords Magnetosphere, Plasma, Magnetospheric convection, Storms and substorms, Ener- getic particles 1 Outline of the Formation of the in the southern hemisphere. Magnetosphere and the Mag- There is an influx of solar wind plasma netospheric Plasma Structure particles in the lobe region. The area of the lobe near the magnetopause is referred to as The magnetosphere is a distinct region in the mantle. The magnetic field intensity is space surrounding the Earth, and its structure low near the equatorial plane, where the north- has been the subject of numerous detailed ern and southern lobes meet. Hot plasma satellite observations. Fig.1 shows a represen- accumulates in this region, referred to as the tation of this structure, with the upper front plasma sheet. Characteristic plasma regimes quarter removed to show the interior. The are present near the Earth, with plasma with Earth is at the center, and the solar wind flows higher energies relative to the plasma sheet.
    [Show full text]
  • Space Physics Handout 2 : the Earth's Magnetosphere And
    Space Physics Handout 2 : The Earth’s magnetosphere and ionosphere The previous handout discussed the highly conducting plasma which the Sun emits, known as the solar wind. This highly conducting plasma travels at supersonic speeds of about 500 km/s as a result of the supersonic expansion of the solar corona. As a result of this plasma being highly conductive, the solar wind magnetic field is frozen into the plasma (something we will discuss and derive in the lectures). The implication of this is that when the solar wind encounters the dipolar magnetic field of the Earth, that it simply cannot penetrate through it and what happens is that it is slowed down and to a large extent deflected around it. Since the solar wind hits the obstacle (the Earth’s magnetic field) at supersonic speeds, a shock wave is formed, which is known as the bow shock. At this bow shock the solar wind plasma is slowed down and a substantial fraction of the kinetic energy of the particles is converted into thermal energy. The region of thermalised subsonic plasma behind the bow shock is called the magnetosheath. The magnetosheath plasma is denser and hotter than the solar wind plasma and the magnetic field values are higher in this region compared to out in the solar wind. The shocked solar wind plasma in the magnetosheath cannot easily penetrate the Earth’s magnetic field and is deflected around it. The boundary separating the two different regions is called the magnetopause and the cavity generated by the solar wind interaction with the Earth’s magnetic field is known as the magnetosphere.
    [Show full text]
  • Temperature Variations in the Dayside Magnetosheath and Their
    Journal of Geophysical Research: Space Physics RESEARCH ARTICLE Temperature variations in the dayside magnetosheath 10.1002/2016JA023729 and their dependence on ion-scale magnetic structures: Key Points: THEMIS statistics and measurements by MMS • A positive correlation exists between the amplitude of magnetic fluctuations and temperature A. P. Dimmock1 , A. Osmane1 , T. I. Pulkkinen1 , K. Nykyri2 , and E. Kilpua3 variation • Temperature fluctuations are strongly 1 associated with larger local in Department of Electronics and Nanoengineering, School of Electrical Engineering, Aalto University, Espoo, Finland, 2 ion-scale magnetic structures than Centre for Space and Atmospheric Research, Embry-Riddle Aeronautical University, Daytona Beach, Florida, USA, the fluid input at the shock 3Department of Physics, University of Helsinki, Helsinki, Finland • The amplitude of ion gyroscale fluctuations and in situ temperature variations are favored by the Abstract The magnetosheath contains an array of waves, instabilities, and nonlinear magnetic dawn flank structures which modify global plasma properties by means of various wave-particle interactions. The present work demonstrates that ion-scale magnetic field structures (∼0.2–0.5 Hz) observed in the dayside Correspondence to: A. P. Dimmock, magnetosheath are statistically correlated to ion temperature changes on orders 10–20% of the andrew.dimmock@aalto.fi background value. In addition, our statistical analysis implies that larger temperature changes are in equipartition to larger amplitude magnetic structures. This effect was more pronounced behind the Citation: quasi-parallel bow shock and during faster solar wind speeds. The study of two separate intervals suggests Dimmock, A. P., A. Osmane, that this effect can result from both local and external drivers.
    [Show full text]
  • Predominance of ECH Wave Contribution to Diffuse Aurora in Earth's Outer Magnetosphere
    UCLA UCLA Previously Published Works Title Predominance of ECH wave contribution to diffuse aurora in Earth's outer magnetosphere Permalink https://escholarship.org/uc/item/8fx1f8cz Journal Journal of Geophysical Research: Space Physics, 120(1) ISSN 2169-9380 Authors Zhang, XJ Angelopoulos, V Ni, B et al. Publication Date 2015 DOI 10.1002/2014JA020455 Peer reviewed eScholarship.org Powered by the California Digital Library University of California PUBLICATIONS Journal of Geophysical Research: Space Physics RESEARCH ARTICLE Predominance of ECH wave contribution to diffuse 10.1002/2014JA020455 aurora in Earth’s outer magnetosphere Key Points: Xiao-Jia Zhang1,2, Vassilis Angelopoulos1, Binbin Ni3, and Richard M. Thorne2 • The role of ECH waves in driving fi diffuse aurora is quanti ed globally 1Department of Earth, Planetary, and Space Sciences and Institute of Geophysics and Space Physics, University of California, • ECH waves are the dominant driver of 2 diffuse aurora in the outer Los Angeles, California, USA, Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, 3 magnetosphere California, USA, Department of Space Physics, School of Electronic Information, Wuhan University, Wuhan, Hubei, China • Relative contribution of high-latitude precipitation decreases in active times Abstract Due to its importance for global energy dissipation in the ionosphere, the diffuse aurora has been intensively studied in the past 40 years. Its origin (precipitation of 0.5–10 keV electrons from the Correspondence to: plasma sheet without potential acceleration) has been generally attributed to whistler-mode chorus wave X.-J. Zhang, scattering in the inner magnetosphere (R < ~8 RE), while the scattering mechanism beyond that distance [email protected] remains unresolved.
    [Show full text]
  • On the Relationship of the Plasmapause to the Equatorward
    JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 87, NO. All, PAGES 9059-9069, NOVEMBER l, 1982 On the Relationship of the Plasmapauseto the Equatorward Boundary of the Auroral Oval and to the Inner Edge of the Plasma Sheet J. L. HORWlTZ,1 W. K. Co• 2 C R BAUGHER,3 C R. CHAPPELL3 L A FRANK,4 T. E. EASTMAN,4 R. R. ANDERSON,4 E.G. SHELLEY,5 AND D. T. YOUNG6 ISEE 1 observations of the plasmapause are compared with simultaneous observations of the electron plasma sheet and also the auroral oval observed in DMSP photographs. Only a limited amount of appropriate data was available for the comparisons: the plasmapause/plasmasheet inner edge comparisonswere restricted to the early and late morning sectors, while there were two satisfactory comparisons of the plasmapauseand the equatorward boundary of the auroral oval in the evening sector. However, these examples indicate that the plasmapauselocation often coincides to within zXL- 0.1-0.2 with both the plasma sheet inner boundary and the field line threading the equatorward boundary of the auroral oval. This co-location of the plasmapauseand the plasma sheet inner edge may be due to shielding of the magnetosphericconvection electric field by an Alfv6n layer located at the inner edge of the plasma sheet as discussedby Jaggi and Wolf (1973) and others. INTRODUCTION sheet population and inhomogeneous ionospheric electrical The locations of both the plasmapauseand the earthward conductivities together cause a modification of the magneto- edge of the plasma sheet are sensitive indicators of large- spheric electric field distribution in which the earthward scale magnetospheric convection electric fields [Axford, edge of the plasma sheet coincides with an 'Alfv6n layer' 1969].
    [Show full text]
  • A Review of Recent Studies on Coronal Dynamics: Streamers, Coronal Mass Ejections, and Their Interactions
    Review Progress of Projects Supported by NSFC May 2013 Vol.58 No.14: 15991624 Geophysics doi: 10.1007/s11434-013-5669-6 A review of recent studies on coronal dynamics: Streamers, coronal mass ejections, and their interactions CHEN Yao Institute of Space Sciences and School of Space Science and Physics, Shandong University, Weihai 264209, China Received October 8, 2012; accepted December 25, 2012; published online March 26, 2013 In this article I present a review of recent studies on coronal dynamics, including research progresses on the physics of coronal streamers that are the largest structure in the corona, physics of coronal mass ejections (CMEs) that may cause a global disturb- ance to the corona, as well as physics of CME-streamer interactions. The following topics will be discussed in depth: (1) accelera- tion of the slow wind flowing around the streamer considering the effect of magnetic flux tube curvature; (2) physical mechanism accounting for persistent releases of streamer blobs and diagnostic results on the temporal variability of the slow wind speed with such events; (3) force balance analysis and energy release mechanism of CMEs with a flux rope magnetohydrodynamic model; (4) statistical studies on magnetic islands along the coronal-ray structure behind a CME and the first observation of magnetic island coalescence with associated electron acceleration; and (5) white light and radio manifestations of CME-streamer interactions. These studies shed new light on the physics of coronal streamers, the acceleration of the slow wind, the physics of solar eruptions, the physics of magnetic reconnection and associated electron acceleration, the large-scale coronal wave phenomenon, as well as the physics accounting for CME shock-induced type II radio bursts.
    [Show full text]