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Global Empirical Picture of Magnetospheric Substorms Inferred From Multimission Magnetometer Data
Sitnov, M. I.; Tsyganenko, N. A.; Stephens, G. K. +4 more
Magnetospheric substorms represent key explosive processes in the interaction of the Earth's magnetosphere with the solar wind, and their understanding and modeling are critical for space weather forecasting. During substorms, the magnetic field on the nightside is first stretched in the antisunward direction and then it rapidly contracts earthwar…
MAVEN and MEX Multi-instrument Study of the Dayside of the Martian Induced Magnetospheric Structure Revealed by Pressure Analyses
André, N.; Fedorov, A.; Barabash, S. +9 more
A combination of statistical studies and 18 case studies have been used to investigate the structure of the induced Martian magnetosphere. The different plasma and magnetic pressure forces on the dayside of the induced magnetosphere of Mars have been studied using 3.5 years of Mars Atmosphere and Volatile Evolution (MAVEN) and Mars Express (MEX) o…
SWAN/SOHO Lyman-α Mapping: The Hydrogen Geocorona Extends Well Beyond the Moon
Schmidt, W.; Bertaux, J. -L.; Quémerais, E. +2 more
The Earth's hydrogen exosphere Lyman-α radiation was mapped with the Solar Wind Anisotropies/Solar and Heliospheric Observatory (SWAN/SOHO) instrument in January 1996, 1997, and 1998 (low solar activity). The use of a hydrogen absorption cell allowed to disentangle the interplanetary emission from the geocoronal one and to assign the absorbed sign…
Origin of the Extended Mars Radar Blackout of September 2017
Leblanc, François; Witasse, Olivier; Sánchez-Cano, Beatriz +13 more
The Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) onboard Mars Express, which operates between 0.1 and 5.5 MHz, suffered from a complete blackout for 10 days in September 2017 when observing on the nightside (a rare occurrence). Moreover, the Shallow Radar (SHARAD) onboard the Mars Reconnaissance Orbiter, which operates at 20…
The Martian Bow Shock Over Solar Cycle 23-24 as Observed by the Mars Express Mission
Holmström, M.; Wild, J. A.; Lester, M. +2 more
The Martian bow shock position is known to be correlated with solar extreme ultraviolet irradiance. Since this parameter is also correlated with the evolution of the solar cycle, it is expected that the Martian bow shock position should also vary over such a period. However, previous reports on this topic have often proved contradictory. Using 13 …
Nighttime Magnetic Perturbation Events Observed in Arctic Canada: 2. Multiple-Instrument Observations
Russell, C. T.; Kistler, L. M.; Fazakerley, A. +14 more
The rapid changes of magnetic fields associated with nighttime magnetic perturbations with amplitudes |ΔB| of hundreds of nanoteslas and 5- to 10-min periods can induce bursts of geomagnetically induced currents that can harm technological systems. This paper presents three cases of intervals of intense and complex nighttime magnetic perturbations…
Signatures of Nonideal Plasma Evolution During Substorms Obtained by Mining Multimission Magnetometer Data
Merkin, V. G.; Sitnov, M. I.; Genestreti, K. J. +5 more
Substorm-type evolution of the Earth's magnetosphere is investigated by mining more than two decades (1995-2017) of spaceborne magnetometer data from multiple missions including the first two years (2016-2017) of the Magnetospheric MultiScale mission. This investigation reveals interesting features of plasma evolution distinct from ideal magnetohy…
Helios Observations of Quasiperiodic Density Structures in the Slow Solar Wind at 0.3, 0.4, and 0.6 AU
Arge, C. N.; MacNeice, P.; Di Matteo, S. +3 more
Following previous investigations of quasiperiodic plasma density structures in the solar wind at 1 AU, we show using the Helios1 and Helios2 data their first identification in situ in the inner heliosphere at 0.3, 0.4, and 0.6 AU. We present five events of quasiperiodic density structures with time scales ranging from a few minutes to a couple of…
Properties of Magnetic Reconnection and FTEs on the Dayside Magnetopause With and Without Positive IMF Bx Component During Southward IMF
Kilpua, E. K. J.; Fear, R. C.; Palmroth, M. +11 more
This paper describes properties and behavior of magnetic reconnection and flux transfer events (FTEs) on the dayside magnetopause using the global hybrid-Vlasov code Vlasiator. We investigate two simulation runs with and without a sunward (positive) Bx component of the interplanetary magnetic field (IMF) when the IMF is southward. The r…
Characteristics of the Flank Magnetopause: THEMIS Observations
Haaland, S.; Runov, A.; Angelopoulos, V. +1 more
The terrestrial magnetopause is the boundary that shields the Earth's magnetosphere on one side from the shocked solar wind and its embedded interplanetary magnetic field on the other side. In this paper, we show observations from two of the Time History of Events and Macroscales Interactions during Substorms (THEMIS) satellites, comparing dayside…