Found 8 entries in the Bibliography.

Showing entries from 1 through 8


Diagnosis of ULF Wave-Particle Interactions With Megaelectron Volt Electrons: The Importance of Ultrahigh-Resolution Energy Channels

Electron flux measurements are an important diagnostic for interactions between ultralow-frequency (ULF) waves and relativistic (\~1 MeV) electrons. Since measurements are collected by particle detectors with finite energy channel width, they are affected by a phase mixing process that can obscure these interactions. We demonstrate that ultrahigh-resolution electron measurements from the Magnetic Electron Ion Spectrometer on the Van Allen Probes mission\textemdashobtained using a data product that improves the energy resolut ...

Hartinger, M.; Claudepierre, S.; Turner, D.; Reeves, G.; Breneman, A.; Mann, I.; Peek, T.; Chang, E.; Blake, J.; Fennell, J.; O\textquoterightBrien, T.; Looper, M.;

YEAR: 2018     DOI: 10.1029/2018GL080291

drift resonance; particle detector; Pc5; Radiation belts; ULF wave; Van Allen Probes; Wave-particle interaction

MMS, Van Allen Probes, GOES 13, and Ground Based Magnetometer Observations of EMIC Wave Events Before, During, and After a Modest Interplanetary Shock

The stimulation of EMIC waves by a magnetospheric compression is perhaps the closest thing to a controlled experiment that is currently possible in magnetospheric physics, in that one prominent factor that can increase wave growth acts at a well-defined time. We present a detailed analysis of EMIC waves observed in the outer dayside magnetosphere by the four Magnetosphere Multiscale (MMS) spacecraft, Van Allen Probe A, and GOES 13, and by four very high latitude ground magnetometer stations in the western hemisphere before, ...

Engebretson, M.; Posch, J.; Capman, N.; Campuzano, N.; elik, P.; Allen, R.; Vines, S.; Anderson, B.; Tian, S.; Cattell, C.; Wygant, J.; Fuselier, S.; Argall, M.; Lessard, M.; Torbert, R.; Moldwin, M.; Hartinger, M.; Kim, H.; Russell, C.; Kletzing, C.; Reeves, G.; Singer, H.;

YEAR: 2018     DOI: 10.1029/2018JA025984

Van Allen Probes

Roles of Flow Braking, Plasmaspheric Virtual Resonances, and Ionospheric Currents in Producing Ground Pi2 Pulsations

In one model, Pi2 pulsations are driven pulse by pulse by fast mode pulses that are launched as periodic bursty bulk flows brake when they approach the Earth. We have examined this model by analyzing data from multiple spacecraft and ground magnetometers for a Pi2 pulsation event. During the event, which started at \~2226 UT on 8 November 2014, Time History of Events and Macroscale Interactions during Substorms (THEMIS)-D detected an \~2 min period plasma bulk flow oscillation in the near-Earth magnetotail, while THEMIS-E an ...

Takahashi, Kazue; Hartinger, Michael; Vellante, Massimo; Heilig, azs; Lysak, Robert; Lee, Dong-Hun; Smith, Charles;

YEAR: 2018     DOI: 10.1029/2018JA025664

Van Allen Probes

Observation and Numerical Simulation of Cavity Mode Oscillations Excited by an Interplanetary Shock

Cavity mode oscillations (CMOs) are basic magnetohydrodynamic eigenmodes in the magnetosphere predicted by theory and are expected to occur following the arrival of an interplanetary shock. However, observational studies of shock-induced CMOs have been sparse. We present a case study of a dayside ultra-low-frequency (ULF) wave event that exhibited CMO properties. The event occurred immediately following the arrival of an interplanetary shock at 0829 UT on 15 August 2015. The shock was observed in the solar wind by the Time H ...

Takahashi, Kazue; Lysak, Robert; Vellante, Massimo; Kletzing, Craig; Hartinger, Michael; Smith, Charles;

YEAR: 2018     DOI: 10.1002/2017JA024639

Cavity mode oscillations; interplanetary shock; Van Allen Probes


A multi-spacecraft event study of Pc5 ultra low frequency waves in the magnetosphere and their external drivers

We investigate a quiet-time event of magnetospheric Pc5 ultra low frequency (ULF) waves and their likely external drivers using multiple spacecraft observations. Enhancements of electric and magnetic field perturbations in two narrow frequency bands, 1.5-2 mHz and 3.5-4 mHz, were observed over a large radial distance range from r ~5 to 11 RE. During the first half of this event, perturbations were mainly observed in the transverse components and only in the 3.5-4 mHz band. In comparison, enhancements were stronger during the ...

Wang, Chih-Ping; Thorne, Richard; Liu, Terry; Hartinger, Michael; Nagai, Tsugunobu; Angelopoulos, Vassilis; Wygant, John; Breneman, Aaron; Kletzing, Craig; Reeves, Geoffrey; Claudepierre, Seth; Spence, Harlan;

YEAR: 2017     DOI: 10.1002/2016JA023610

IMF discontinuity; inner magnetosphere; Kelvin-Helmholtz vortices; magnetosheath; Pc5 waves; plasma sheet; Van Allen Probes


Propagation of ULF waves from the upstream region to the midnight sector of the inner magnetosphere

Ultralow frequency (ULF) waves generated in the ion foreshock are a well-known source of Pc3-Pc4 waves (7\textendash100 mHz) observed in the dayside magnetosphere. We use data acquired on 10 April 2013 by multiple spacecraft to demonstrate that ULF waves of upstream origin can propagate to the midnight sector of the inner magnetosphere. At 1130\textendash1730 UT on the selected day, the two Van Allen Probes spacecraft and the geostationary ETS-VIII satellite detected compressional 20 to 40 mHz magnetic field oscillations bet ...

Takahashi, Kazue; Hartinger, Michael; Malaspina, David; Smith, Charles; Koga, Kiyokazu; Singer, Howard; ├╝hauff, Dennis; Baishev, Dmitry; Moiseev, Alexey; Yoshikawa, Akimasa;

YEAR: 2016     DOI: 10.1002/2016JA022958

midnight sector; Pc3 waves; plasmasphere; upstream waves; Van Allen Probes


THEMIS measurements of quasi-static electric fields in the inner magnetosphere

We use four years of THEMIS double-probe measurements to offer, for the first time, a complete picture of the dawn-dusk electric field covering all local times and radial distances in the inner magnetosphere based on in situ equatorial observations. This study is motivated by the results from the CRRES mission, which revealed a local maximum in the electric field developing near Earth during storm times, rather than the expected enhancement at higher L shells that is shielded near Earth as suggested by the Volland-Stern mode ...

Califf, S.; Li, X.; Blum, L.; Jaynes, A.; Schiller, Q.; Zhao, H.; Malaspina, D.; Hartinger, M.; Wolf, R.; Rowland, D.; Wygant, J.; Bonnell, J.;

YEAR: 2014     DOI: 10.1002/2014JA020360

convection; double probe; electric field; inner magnetosphere


Explaining sudden losses of outer radiation belt electrons during geomagnetic storms

The Van Allen radiation belts were first discovered in 1958 by the Explorer series of spacecraft1. The dynamic outer belt consists primarily of relativistic electrons trapped by the Earth\textquoterights magnetic field. Magnetospheric processes driven by the solar wind2 cause the electron flux in this belt to fluctuate substantially over timescales ranging from minutes to years3. The most dramatic of these events are known as flux \textquoterightdropouts\textquoteright and often occur during geomagnetic storms. During such a ...

Turner, Drew; Shprits, Yuri; Hartinger, Michael; Angelopoulos, Vassilis;

YEAR: 2012     DOI: 10.1038/nphys2185