Energetic Particle Dynamics in Mercurys Magnetosphere
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Marina Galand
Thermosphere - Ionosphere - Magnetosphere Coupling! Canada M. Galand (1), I.C.F. Müller-Wodarg (1), L. Moore (2), M. Mendillo (2), S. Miller (3) , L.C. Ray (1) (1) Department of Physics, Imperial College London, London, U.K. (2) Center for Space Physics, Boston University, Boston, MA, USA (3) Department of Physics and Astronomy, University College London, U.K. 1." Energy crisis at giant planets Credit: NASA/JPL/Space Science Institute 2." TIM coupling Cassini/ISS (false color) 3." Modeling of IT system 4." Comparison with observaons Cassini/UVIS 5." Outstanding quesAons (Pryor et al., 2011) SATURN JUPITER (Gladstone et al., 2007) Cassini/UVIS [UVIS team] Cassini/VIMS (IR) Credit: J. Clarke (BU), NASA [VIMS team/JPL, NASA, ESA] 1. SETTING THE SCENE: THE ENERGY CRISIS AT THE GIANT PLANETS THERMAL PROFILE Exosphere (EARTH) Texo 500 km Key transiLon region Thermosphere between the space environment and the lower atmosphere Ionosphere 85 km Mesosphere 50 km Stratosphere ~ 15 km Troposphere SOLAR ENERGY DEPOSITION IN THE UPPER ATMOSPHERE Solar photons ion, e- Neutral Suprathermal electrons B ion, e- Thermal e- Ionospheric Thermosphere Ne, Nion e- heang Te P, H * + Airglow Neutral atmospheric Exothermic reacAons heang IS THE SUN THE MAIN ENERGY SOURCE OF PLANERATY THERMOSPHERES? W Main energy source: UV solar radiaon Main energy source? EartH Outer planets CO2 atmospHeres Exospheric temperature (K) [aer Mendillo et al., 2002] ENERGY CRISIS AT THE GIANT PLANETS Observed values at low to mid-latudes solsce equinox Modeled values (Sun only) [Aer -
A Future Mars Environment for Science and Exploration
Planetary Science Vision 2050 Workshop 2017 (LPI Contrib. No. 1989) 8250.pdf A FUTURE MARS ENVIRONMENT FOR SCIENCE AND EXPLORATION. J. L. Green1, J. Hol- lingsworth2, D. Brain3, V. Airapetian4, A. Glocer4, A. Pulkkinen4, C. Dong5 and R. Bamford6 (1NASA HQ, 2ARC, 3U of Colorado, 4GSFC, 5Princeton University, 6Rutherford Appleton Laboratory) Introduction: Today, Mars is an arid and cold world of existing simulation tools that reproduce the physics with a very thin atmosphere that has significant frozen of the processes that model today’s Martian climate. A and underground water resources. The thin atmosphere series of simulations can be used to assess how best to both prevents liquid water from residing permanently largely stop the solar wind stripping of the Martian on its surface and makes it difficult to land missions atmosphere and allow the atmosphere to come to a new since it is not thick enough to completely facilitate a equilibrium. soft landing. In its past, under the influence of a signif- Models hosted at the Coordinated Community icant greenhouse effect, Mars may have had a signifi- Modeling Center (CCMC) are used to simulate a mag- cant water ocean covering perhaps 30% of the northern netic shield, and an artificial magnetosphere, for Mars hemisphere. When Mars lost its protective magneto- by generating a magnetic dipole field at the Mars L1 sphere, three or more billion years ago, the solar wind Lagrange point within an average solar wind environ- was allowed to directly ravish its atmosphere.[1] The ment. The magnetic field will be increased until the lack of a magnetic field, its relatively small mass, and resulting magnetotail of the artificial magnetosphere its atmospheric photochemistry, all would have con- encompasses the entire planet as shown in Figure 1. -
Diffuse Electron Precipitation in Magnetosphere-Ionosphere- Thermosphere Coupling
EGU21-6342 https://doi.org/10.5194/egusphere-egu21-6342 EGU General Assembly 2021 © Author(s) 2021. This work is distributed under the Creative Commons Attribution 4.0 License. Diffuse electron precipitation in magnetosphere-ionosphere- thermosphere coupling Dong Lin1, Wenbin Wang1, Viacheslav Merkin2, Kevin Pham1, Shanshan Bao3, Kareem Sorathia2, Frank Toffoletto3, Xueling Shi1,4, Oppenheim Meers5, George Khazanov6, Adam Michael2, John Lyon7, Jeffrey Garretson2, and Brian Anderson2 1High Altitude Observatory, National Center for Atmospheric Research, Boulder CO, United States of America 2Applied Physics Laboratory, Johns Hopkins University, Laurel MD, USA 3Department of Physics and Astronomy, Rice University, Houston TX, USA 4Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg VA, USA 5Astronomy Department, Boston University, Boston MA, USA 6Goddard Space Flight Center, NASA, Greenbelt MD, USA 7Department of Physics and Astronomy, Dartmouth College, Hanover NH, USA Auroral precipitation plays an important role in magnetosphere-ionosphere-thermosphere (MIT) coupling by enhancing ionospheric ionization and conductivity at high latitudes. Diffuse electron precipitation refers to scattered electrons from the plasma sheet that are lost in the ionosphere. Diffuse precipitation makes the largest contribution to the total precipitation energy flux and is expected to have substantial impacts on the ionospheric conductance and affect the electrodynamic coupling between the magnetosphere and ionosphere-thermosphere. -
Solar Wind Magnetosphere Coupling
Solar Wind Magnetosphere Coupling F. Toffoletto, Rice University Figure courtesy T. W. Hill with thanks to R. A. Wolf and T. W. Hill, Rice U. Outline • Introduction • Properties of the Solar Wind Near Earth • The Magnetosheath • The Magnetopause • Basic Physical Processes that control Solar Wind Magnetosphere Coupling – Open and Closed Magnetosphere Processes – Electrodynamic coupling – Mass, Momentum and Energy coupling – The role of the ionosphere • Current Status and Summary QuickTime™ and a YUV420 codec decompressor are needed to see this picture. Introduction • By virtue of our proximity, the Earth’s magnetosphere is the most studied and perhaps best understood magnetosphere – The system is rather complex in its structure and behavior and there are still some basic unresolved questions – Today’s lecture will focus on describing the coupling to the major driver of the magnetosphere - the solar wind, and the ionosphere – Monday’s lecture will look more at the more dynamic (and controversial) aspect of magnetospheric dynamics: storms and substorms The Solar Wind Near the Earth Solar-Wind Properties Observed Near Earth • Solar wind parameters observed by many spacecraft over period 1963-86. From Hapgood et al. (Planet. Space Sci., 39, 410, 1991). Solar Wind Observed Near Earth Values of Solar-Wind Parameters Parameter Minimum Most Maximum Probable Velocity v (km/s) 250 370 2000× Number density n (cm-3) 683 Ram pressure rv2 (nPa)* 328 Magnetic field strength B 0 6 85 (nanoteslas) IMF Bz (nanoteslas) -31 0¤ 27 * 1 nPa = 1 nanoPascal = 10-9 Newtons/m2. Indicates at least one interval with B < 0.1 nT. ¤ Mean value was 0.014 nT, with a standard deviation of 3.3 nT. -
Planetary Magnetospheres
CLBE001-ESS2E November 9, 2006 17:4 100-C 25-C 50-C 75-C C+M 50-C+M C+Y 50-C+Y M+Y 50-M+Y 100-M 25-M 50-M 75-M 100-Y 25-Y 50-Y 75-Y 100-K 25-K 25-19-19 50-K 50-40-40 75-K 75-64-64 Planetary Magnetospheres Margaret Galland Kivelson University of California Los Angeles, California Fran Bagenal University of Colorado, Boulder Boulder, Colorado CHAPTER 28 1. What is a Magnetosphere? 5. Dynamics 2. Types of Magnetospheres 6. Interaction with Moons 3. Planetary Magnetic Fields 7. Conclusions 4. Magnetospheric Plasmas 1. What is a Magnetosphere? planet’s magnetic field. Moreover, unmagnetized planets in the flowing solar wind carve out cavities whose properties The term magnetosphere was coined by T. Gold in 1959 are sufficiently similar to those of true magnetospheres to al- to describe the region above the ionosphere in which the low us to include them in this discussion. Moons embedded magnetic field of the Earth controls the motions of charged in the flowing plasma of a planetary magnetosphere create particles. The magnetic field traps low-energy plasma and interaction regions resembling those that surround unmag- forms the Van Allen belts, torus-shaped regions in which netized planets. If a moon is sufficiently strongly magne- high-energy ions and electrons (tens of keV and higher) tized, it may carve out a true magnetosphere completely drift around the Earth. The control of charged particles by contained within the magnetosphere of the planet. -
Juno Observations of Large-Scale Compressions of Jupiter's Dawnside
PUBLICATIONS Geophysical Research Letters RESEARCH LETTER Juno observations of large-scale compressions 10.1002/2017GL073132 of Jupiter’s dawnside magnetopause Special Section: Daniel J. Gershman1,2 , Gina A. DiBraccio2,3 , John E. P. Connerney2,4 , George Hospodarsky5 , Early Results: Juno at Jupiter William S. Kurth5 , Robert W. Ebert6 , Jamey R. Szalay6 , Robert J. Wilson7 , Frederic Allegrini6,7 , Phil Valek6,7 , David J. McComas6,8,9 , Fran Bagenal10 , Key Points: Steve Levin11 , and Scott J. Bolton6 • Jupiter’s dawnside magnetosphere is highly compressible and subject to 1Department of Astronomy, University of Maryland, College Park, College Park, Maryland, USA, 2NASA Goddard Spaceflight strong Alfvén-magnetosonic mode Center, Greenbelt, Maryland, USA, 3Universities Space Research Association, Columbia, Maryland, USA, 4Space Research coupling 5 • Magnetospheric compressions may Corporation, Annapolis, Maryland, USA, Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa, USA, 6 7 enhance reconnection rates and Southwest Research Institute, San Antonio, Texas, USA, Department of Physics and Astronomy, University of Texas at San increase mass transport across the Antonio, San Antonio, Texas, USA, 8Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey, USA, magnetopause 9Office of the VP for the Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey, USA, • Total pressure increases inside the 10Laboratory for Atmospheric and Space Physics, University of Colorado -
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. -
Mercury Friday, February 23
ASTRONOMY 161 Introduction to Solar System Astronomy Class 18 Mercury Friday, February 23 Mercury: Basic characteristics Mass = 3.302×1023 kg (0.055 Earth) Radius = 2,440 km (0.383 Earth) Density = 5,427 kg/m³ Sidereal rotation period = 58.6462 d Albedo = 0.11 (Earth = 0.39) Average distance from Sun = 0.387 A.U. Mercury: Key Concepts (1) Mercury has a 3-to-2 spin-orbit coupling (not synchronous rotation). (2) Mercury has no permanent atmosphere because it is too hot. (3) Like the Moon, Mercury has cratered highlands and smooth plains. (4) Mercury has an extremely large iron-rich core. (1) Mercury has a 3-to-2 spin-orbit coupling (not synchronous rotation). Mercury is hard to observe from the Earth (because it is so close to the Sun). Its rotation speed can be found from Doppler shift of radar signals. Mercury’s unusual orbit Orbital period = 87.969 days Rotation period = 58.646 days = (2/3) x 87.969 days Mercury is NOT in synchronous rotation (1 rotation per orbit). Instead, it has 3-to-2 spin-orbit coupling (3 rotations for 2 orbits). Synchronous rotation (WRONG!) 3-to-2 spin-orbit coupling (RIGHT!) Time between one noon and the next is 176 days. Sun is above the horizon for 88 days at the time. Daytime temperatures reach as high as: 700 Kelvin (800 degrees F). Nighttime temperatures drops as low as: 100 Kelvin (-270 degrees F). (2) Mercury has no permanent atmosphere because it is too hot (and has low escape speed). Temperature is a measure of the 3kT v = random speed of m atoms (or v typical speed of atom molecules). -
Mariner 10 Observations of Field-Aligned Currents at Mercury
Planet. Space Sci., Vol. 45, No. 1, pp. 133-141, 1997 Pergamon #I? 1997 Published bv Elsevier Science Ltd P&ted in Great Brit& All rights reserved 0032-0633/97 $17.00+0.00 PII: S0032-0633(96)00104-3 Mariner 10 observations of field-aligned currents at Mercury J. A. Slavin,’ J. C. J. Owen,’ J. E. P. Connerney’ and S. P. Christon ‘Laboratory for Extraterrestrial Physics, NASA/GSFC, Greenbelt, MD 20771, U.S.A. ‘Astronomy Unit, Queen Mary and Westfield College, London, U.K. 3Department of Physics, University of Maryland, College Park, MD 20742, U.S.A. Received 5 October 1995; revised 11 April 1996; accepted 13 April 1996 magnetic field at Mercury with a dipole moment of about 300nT R& (see review by Connerney and Ness (1988)). This magnetic field is sufficient to stand-off the average solar wind at an altitude of about 1 RM as depicted in Fig. 1 (see review by Russell et al. (1988)). For the purposes of comparison the diameter of the Earth is indicated at the bottom of the figure (i.e. 1 RE = 6380 km ; 1 RM = 2439 km). Whether or not the solar wind is ever able to compress and/or erode the dayside magnetosphere to the point where solar wind ions could directly impact the surface remains a topic of considerable controversy (Siscoe and Christopher, 1975 ; Slavin and Holzer, 1979 ; Hood and Schubert, 1979; Suess and Goldstein, 1979; Goldstein et al., 1981). Overall, the basic morphology of this small mag- netosphere appears quite similar to that of the Earth. -
Earth's Magnetosphere
OCM BOCES Science Center Magnetosphere: The Earth’s Magnetic Field Solar Wind and the Earth’s Magnetosphere What is the Earth’s Magnetosphere? The Earth has a magnetic force field around it. This force field surrounds the Earth. The Earth is a sphere so we call this magnetic force field the magnetosphere. The magnetosphere helps to protect the Earth. It protects us from the Solar Wind. What is the solar wind? . It is a stream of particles that flow out from the Sun . It pushes on and shapes the Earth’s magnetosphere (shown in blue lines). The magnetosphere acts like a shield. Are the solar winds always the same? Solar winds can change. Sometimes there are blasts of particles called Coronal Mass Ejections (CME’s) . CMEs are clouds of charged gases that explode from the Sun. They send out billions of kilograms of matter into space. These blasts cause geomagnetic storms that disrupt the Earth’s magnetosphere. What happens when a CME hits the Earth? It takes 2 to 4 days for a CME blast to reach Earth. The bluish lines trace the shape of Earth’s magnetosphere (its magnetic field.) It is disrupted and distorted by the blast. During these very violent storms on the Sun, the number of CMEs becomes very high. Some of the particles actually get pulled into the Earth’s atmosphere through the magnetosphere. A lot of energy is released from these particles. During a geomagnetic storm, lots of electrical activity (energy release) can be seen from space over the U.S. and elsewhere on Earth. -
THEMIS ESA First Science Results and Performance Issues
Space Sci Rev DOI 10.1007/s11214-008-9433-1 THEMIS ESA First Science Results and Performance Issues J.P. McFadden · C.W. Carlson · D. Larson · J. Bonnell · F. Mozer · V. Angelopoulos · K.-H. Glassmeier · U. Auster Received: 5 April 2008 / Accepted: 25 August 2008 © Springer Science+Business Media B.V. 2008 Abstract Early observations by the THEMIS ESA plasma instrument have revealed new details of the dayside magnetosphere. As an introduction to THEMIS plasma data, this pa- per presents observations of plasmaspheric plumes, ionospheric ion outflows, field line reso- nances, structure at the low latitude boundary layer, flux transfer events at the magnetopause, and wave and particle interactions at the bow shock. These observations demonstrate the ca- pabilities of the plasma sensors and the synergy of its measurements with the other THEMIS experiments. In addition, the paper includes discussions of various performance issues with the ESA instrument such as sources of sensor background, measurement limitations, and data formatting problems. These initial results demonstrate successful achievement of all measurement objectives for the plasma instrument. Keywords THEMIS · Magnetosphere · Magnetopause · Bow shock · Instrument performance PACS 94.80.+g · 06.20.Fb · 94.30.C- · 94.05.-a · 07.87.+v 1 Introduction The THEMIS mission provides the first multi-satellite measurements of the dayside mag- netosphere, magnetopause and bow shock utilizing a string of pearls orbit near the ecliptic plane (Angelopoulos 2008). During a 7 month coast phase, the instruments were commis- sioned and cross-calibrated while spacecraft separations were adjusted from a few hundred J.P. McFadden () · C.W. Carlson · D. -
1 the Lifecycle of Hollows on Mercury
The Lifecycle of Hollows on Mercury: An Evaluation of Candidate Volatile Phases and a Novel Model of Formation. 1 1 2 3 M. S. Phillips , J. E. Moersch , C. E. Viviano , J. P. Emery 1Department of Earth and Planetary Sciences, University of Tennessee, Knoxville 2Planetary Exploration Group, Johns Hopkins University Applied Physics Laboratory 3Department of Astronomy and Planetary Sciences, Northern Arizona University Corresponding author: Michael Phillips ([email protected]) Keywords: Mercury, hollows, thermal model, fumarole. Abstract On Mercury, high-reflectance, flat-floored depressions called hollows are observed nearly globally within low-reflectance material, one of Mercury’s major color units. Hollows are thought to be young, or even currently active, features that form via sublimation, or a “sublimation-like” process. The apparent abundance of sulfides within LRM combined with spectral detections of sulfides associated with hollows suggests that sulfides may be the phase responsible for hollow formation. Despite the association of sulfides with hollows, it is still not clear whether sulfides are the hollow-forming phase. To better understand which phase(s) might be responsible for hollow formation, we calculated sublimation rates for 57 candidate hollow-forming volatile phases from the surface of Mercury and as a function of depth beneath regolith lag deposits of various thicknesses. We found that stearic acid (C18H36O2), fullerenes (C60, C70), and elemental sulfur (S) have the appropriate thermophysical properties to explain hollow formation. Stearic acid and fullerenes are implausible hollow-forming phases because they are unlikely to have been delivered to or generated on Mercury in high enough volume to account for hollows.