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Journal of Geophysical Research. Space Physics

A Varsani, R Nakamura, V A Sergeev, W Baumjohann, C J Owen, A A Petrukovich, Z Yao, T K M Nakamura, M V Kubyshkina, T Sotirelis, J L Burch, K J Genestreti, Z Vörös, M Andriopoulou, D J Gershman, L A Avanov, W Magnes, C T Russell, F Plaschke, Y V Khotyaintsev, B L Giles, V N Coffey, J C Dorelli, R J Strangeway, R B Torbert, P-A Lindqvist, R Ergun
During a magnetic storm on 23 June 2015, several very intense substorms took place, with signatures observed by multiple spacecraft including DMSP and Magnetospheric Multiscale (MMS). At the time of interest, DMSP F18 crossed inbound through a poleward expanding auroral bulge boundary at 23.5 h magnetic local time (MLT), while MMS was located duskward of 22 h MLT during an inward crossing of the expanding plasma sheet boundary. The two spacecraft observed a consistent set of signatures as they simultaneously crossed the reconnection separatrix layer during this very intense reconnection event...
November 2017: Journal of Geophysical Research. Space Physics
R T Desai, M M Cowee, H Wei, X Fu, S P Gary, M Volwerk, A J Coates
In the vicinity of Europa, Galileo observed bursty Alfvén-cyclotron wave power at the gyrofrequencies of a number of species including K+ , O 2+, Na+ , and Cl+ , indicating the localized pickup of these species. Additional evidence for the presence of chlorine was the occurrence of both left-hand (LH) and right-hand (RH) polarized transverse wave power near the Cl+ gyrofrequency, thought to be due to the pickup of both Cl+ and the easily formed chlorine anion, Cl- . To test this hypothesis, we use one-dimensional hybrid (kinetic ion, massless fluid electron) simulations for both positive and negative pickup ions and self-consistently reproduce the growth of both LH and RH Alfvén-cyclotron waves in agreement with linear theory...
October 2017: Journal of Geophysical Research. Space Physics
Philip A Fernandes, Brian A Larsen, Michelle F Thomsen, Ruth M Skoug, Geoffrey D Reeves, Michael H Denton, Reinhard H W Friedel, Herbert O Funsten, Jerry Goldstein, Michael G Henderson, Jörg-Micha Jahn, Elizabeth A MacDonald, David K Olson
The two full precessions in local time completed by the Van Allen Probes enable global specification of the near-equatorial inner magnetosphere plasma environment. Observations by the Helium-Oxygen-Proton-Electron (HOPE) mass spectrometers provide detailed insight into the global spatial distribution of electrons, H+ , He+ , and O+ . Near-equatorial omnidirectional fluxes and abundance ratios at energies 0.1-30 keV are presented for 2 ≤ L ≤ 6 as a function of L shell, magnetic local time (MLT), and geomagnetic activity...
September 2017: Journal of Geophysical Research. Space Physics
Liam M Kilcommons, Robert J Redmon, Delores J Knipp
We have developed a method for reprocessing the multi-decadal, multi-spacecraft Defense Meteorological Satellite Program Magnetometer (DMSP SSM) dataset and have applied it to fifteen spacecraft-years of data (DMSP Flight 16-18, 2010-2014). This Level-2 dataset improves on other available SSM datasets with recalculated spacecraft locations and magnetic perturbations, artifact signal removal, representations of the observations in geomagnetic coordinates, and in-situ auroral boundaries. Spacecraft locations have been recalculated using ground-tracking information...
August 2017: Journal of Geophysical Research. Space Physics
Robert J Redmon, William F Denig, Liam M Kilcommons, Delores J Knipp
Since the mid 1970's, the Defense Meteorological Satellite Program (DMSP) spacecraft have operated instruments for monitoring the space environment from low earth orbit. As the program evolved, so to have the measurement capabilities such that modern DMSP spacecraft include a comprehensive suite of instruments providing estimates of precipitating electron and ion fluxes, cold/bulk plasma composition and moments, the geomagnetic field, and optical emissions in the far and extreme ultraviolet. We describe the creation of a new public database of precipitating electrons and ions from the Special Sensor J (SSJ) instrument, complete with original counts, calibrated differential fluxes adjusted for penetrating radiation, estimates of the total kinetic energy flux and characteristic energy, uncertainty estimates, and accurate ephemerides...
August 2017: Journal of Geophysical Research. Space Physics
Mike Lockwood, Mathew J Owens, Suzanne M Imber, Matthew K James, Emma J Bunce, Timothy K Yeoman
Solar cycle 24 is notable for three features that can be found in previous cycles but which have been unusually prominent: (1) sunspot activity was considerably greater in the northern/southern hemisphere during the rising/declining phase; (2) accumulation of open solar flux (OSF) during the rising phase was modest, but rapid in the early declining phase; (3) the heliospheric current sheet (HCS) tilt showed large fluctuations. We show that these features had a major influence on the progression of the cycle...
June 2017: Journal of Geophysical Research. Space Physics
S A Kiehas, N N Volkonskaya, V S Semenov, N V Erkaev, I V Kubyshkin, I V Zaitsev
We evaluate the large-scale energy budget of magnetic reconnection utilizing an analytical time-dependent impulsive reconnection model and a numerical 2-D MHD simulation. With the generalization to compressible plasma, we can investigate changes in the thermal, kinetic, and magnetic energies. We study these changes in three different regions: (a) the region defined by the outflowing plasma (outflow region, OR), (b) the region of compressed magnetic fields above/below the OR (traveling compression region, TCR), and (c) the region trailing the OR and TCR (wake)...
March 2017: Journal of Geophysical Research. Space Physics
Biagio Forte, Chris Coleman, Susan Skone, Ingemar Häggström, Cathryn Mitchell, Federico Da Dalt, Tommaso Panicciari, Joe Kinrade, Gary Bust
Ionospheric scintillation originates from the scattering of electromagnetic waves through spatial gradients in the plasma density distribution, drifting across a given propagation direction. Ionospheric scintillation represents a disruptive manifestation of adverse space weather conditions through degradation of the reliability and continuity of satellite telecommunication and navigation systems and services (e.g., European Geostationary Navigation Overlay Service, EGNOS). The purpose of the experiment presented here was to determine the contribution of auroral ionization structures to GPS scintillation...
January 2017: Journal of Geophysical Research. Space Physics
N Lugaz, C J Farrugia, R M Winslow, N Al-Haddad, E K J Kilpua, P Riley
We identify all fast-mode forward shocks, whose sheath regions resulted in a moderate (56 cases) or intense (38 cases) geomagnetic storm during 18.5 years from January 1997 to June 2015. We study their main properties, interplanetary causes and geo-effects. We find that half (49/94) such shocks are associated with interacting coronal mass ejections (CMEs), as they are either shocks propagating into a preceding CME (35 cases) or a shock propagating into the sheath region of a preceding shock (14 cases). About half (22/45) of the shocks driven by isolated transients and which have geo-effective sheaths compress pre-existing southward Bz ...
November 2016: Journal of Geophysical Research. Space Physics
V K Jordanova, W Tu, Y Chen, S K Morley, A-D Panaitescu, G D Reeves, C A Kletzing
Mechanisms for electron injection, trapping, and loss in the near-Earth space environment are investigated during the October 2012 "double-dip" storm using our ring current-atmosphere interactions model with self-consistent magnetic field (RAM-SCB). Pitch angle and energy scattering are included for the first time in RAM-SCB using L and magnetic local time (MLT)-dependent event-specific chorus wave models inferred from NOAA Polar-orbiting Operational Environmental Satellites (POES) and Van Allen Probes Electric and Magnetic Field Instrument Suite and Integrated Science observations...
September 2016: Journal of Geophysical Research. Space Physics
J H Westlake, D G Mitchell, P C-Son Brandt, B G Andrews, G Clark
To achieve breakthroughs in the areas of heliospheric and magnetospheric energetic neutral atom (ENA) imaging, a new class of instruments is required. We present a high angular resolution ENA imager concept aimed at the suprathermal plasma populations with energies between 0.5 and 20 keV. This instrument is intended for understanding the spatial and temporal structure of the heliospheric boundary recently revealed by Interstellar Boundary Explorer instrumentation and the Cassini Ion and Neutral Camera. The instrument is also well suited to characterize magnetospheric ENA emissions from low-altitude ENA emissions produced by precipitation of magnetospheric ions into the terrestrial upper atmosphere, or from the magnetosheath where solar wind protons are neutralized by charge exchange, or from portions of the ring current region...
September 2016: Journal of Geophysical Research. Space Physics
Matthew K James, Emma J Bunce, Timothy K Yeoman, Suzanne M Imber, Haje Korth
We present a statistical survey of ultralow-frequency wave activity within the Hermean magnetosphere using the entire MErcury Surface, Space ENvironment, GEochemistry, and Ranging magnetometer data set. This study is focused upon wave activity with frequencies <0.5 Hz, typically below local ion gyrofrequencies, in order to determine if field line resonances similar to those observed in the terrestrial magnetosphere may be present. Wave activity is mapped to the magnetic equatorial plane of the magnetosphere and to magnetic latitude and local times on Mercury using the KT14 magnetic field model...
September 2016: Journal of Geophysical Research. Space Physics
G Clark, I Cohen, J H Westlake, G B Andrews, P Brandt, R E Gold, M A Gkioulidou, R Hacala, D Haggerty, M E Hill, G C Ho, S E Jaskulek, P Kollmann, B H Mauk, R L McNutt, D G Mitchell, K S Nelson, C Paranicas, N Paschalidis, C E Schlemm
Energetic charged particle detectors characterize a portion of the plasma distribution function that plays critical roles in some physical processes, from carrying the currents in planetary ring currents to weathering the surfaces of planetary objects. For several low-resource missions in the past, the need was recognized for a low-resource but highly capable, mass-species-discriminating energetic particle sensor that could also obtain angular distributions without motors or mechanical articulation. This need led to the development of a compact Energetic Particle Detector (EPD), known as the "Puck" EPD (short for hockey puck), that is capable of determining the flux, angular distribution, and composition of incident ions between an energy range of ~10 keV to several MeV...
August 2016: Journal of Geophysical Research. Space Physics
Kyle R Murphy, Ian R Mann, I Jonathan Rae, David G Sibeck, Clare E J Watt
Wave-particle interactions play a crucial role in energetic particle dynamics in the Earth's radiation belts. However, the relative importance of different wave modes in these dynamics is poorly understood. Typically, this is assessed during geomagnetic storms using statistically averaged empirical wave models as a function of geomagnetic activity in advanced radiation belt simulations. However, statistical averages poorly characterize extreme events such as geomagnetic storms in that storm-time ultralow frequency wave power is typically larger than that derived over a solar cycle and Kp is a poor proxy for storm-time wave power...
August 2016: Journal of Geophysical Research. Space Physics
S B Mende, H U Frey, V Angelopoulos
Monochromatic all-sky imagers at South Pole and other Antarctic stations of the Automatic Geophysical Observatory chain recorded the aurora in the region where the Time History of Events and Macroscale Interactions during Substorms (THEMIS) satellites crossed the dayside magnetopause. In several cases the magnetic field lines threading the satellites when mapped to the atmosphere were inside the imagers' field of view. From the THEMIS magnetic field and the plasma density measurements, we were able to locate the position of the magnetopause crossings and map it to the ionosphere using the Tsyganenko-96 field model...
August 2016: Journal of Geophysical Research. Space Physics
Haje Korth, Kim Strohbehn, Francisco Tejada, Andreas G Andreou, John Kitching, Svenja Knappe, S John Lehtonen, Shaughn M London, Matiwos Kafel
A miniature atomic scalar magnetometer based on the rubidium isotope (87)Rb was developed for operation in space. The instrument design implements both Mx and Mz mode operation and leverages a novel microelectromechanical system (MEMS) fabricated vapor cell and a custom silicon-on-sapphire (SOS) complementary metal-oxide-semiconductor (CMOS) integrated circuit. The vapor cell has a volume of only 1 mm(3) so that it can be efficiently heated to its operating temperature by a specially designed, low-magnetic-field-generating resistive heater implemented in multiple metal layers of the transparent sapphire substrate of the SOS-CMOS chips...
August 2016: Journal of Geophysical Research. Space Physics
D N Baker, A N Jaynes, S G Kanekal, J C Foster, P J Erickson, J F Fennell, J B Blake, H Zhao, X Li, S R Elkington, M G Henderson, G D Reeves, H E Spence, C A Kletzing, J R Wygant
Two of the largest geomagnetic storms of the last decade were witnessed in 2015. On 17 March 2015, a coronal mass ejection-driven event occurred with a Dst (storm time ring current index) value reaching -223 nT. On 22 June 2015 another strong storm (Dst reaching -204 nT) was recorded. These two storms each produced almost total loss of radiation belt high-energy (E ≳ 1 MeV) electron fluxes. Following the dropouts of radiation belt fluxes there were complex and rather remarkable recoveries of the electrons extending up to nearly 10 MeV in kinetic energy...
July 2016: Journal of Geophysical Research. Space Physics
C Forsyth, I J Rae, K R Murphy, M P Freeman, C-L Huang, H E Spence, A J Boyd, J C Coxon, C M Jackman, N M E Kalmoni, C E J Watt
Substorms are fundamental and dynamic processes in the magnetosphere, converting captured solar wind magnetic energy into plasma energy. These substorms have been suggested to be a key driver of energetic electron enhancements in the outer radiation belts. Substorms inject a keV "seed" population into the inner magnetosphere which is subsequently energized through wave-particle interactions up to relativistic energies; however, the extent to which substorms enhance the radiation belts, either directly or indirectly, has never before been quantified...
July 2016: Journal of Geophysical Research. Space Physics
D J Andrews, S Barabash, N J T Edberg, D A Gurnett, B E S Hall, M Holmström, M Lester, D D Morgan, H J Opgenoorth, R Ramstad, B Sanchez-Cano, M Way, O Witasse
We present initial analysis and conclusions from plasma observations made during the reported "Mars plume event" of March - April 2012. During this period, multiple independent amateur observers detected a localized, high-altitude "plume" over the Martian dawn terminator [Sanchez-Lavega et al., Nature, 2015, doi:10.1038/nature14162], the cause of which remains to be explained. The estimated brightness of the plume exceeds that expected for auroral emissions, and its projected altitude greatly exceeds that at which clouds are expected to form...
April 2016: Journal of Geophysical Research. Space Physics
A W Smith, C M Jackman, M F Thomsen
Reconnection within planetary magnetotails is responsible for locally energizing particles and changing the magnetic topology. Its role in terms of global magnetospheric dynamics can involve changing the mass and flux content of the magnetosphere. We have identified reconnection related events in spacecraft magnetometer data recorded during Cassini's exploration of Saturn's magnetotail. The events are identified from deflections in the north-south component of the magnetic field, significant above a background level...
April 2016: Journal of Geophysical Research. Space Physics
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