College of Sciences and Mathematics: Recent submissions
Now showing items 261-280 of 393
Global observations of ring current dynamics during corotating interaction region-driven geomagnetic storms in 2008
(2020-06-12)
We examine the evolution of the ring current during the main and early recovery phases of three geomagnetic storms driven by corotating interaction regions. The equatorial energy density profiles of 5-30 keV ions are ...
Evolution of low-altitude and ring current ENA emissions from a moderate magnetospheric storm: Continuous and simultaneous TWINS observations
(2020-06-12)
The moderate storm of 22 July 2009 is the largest measured during the extended solar minimum between December 2006 and March 2010. We present observations of this storm made by the two wide-angle imaging neutral-atom ...
Global-scale hybrid simulation of dayside magnetic reconnection under southward IMF: Structure and evolution of reconnection
(2020-06-12)
Magnetopause reconnection is investigated with our 3-D self-consistent global hybrid simulation model. The magnetic configuration and evolution of Flux Transfer Events (FTEs) and the associated ion density and ion velocity ...
Global-scale hybrid simulation of cusp precipitating ions associated with magnetopause reconnection under southward IMF
(2020-06-09)
With a 3-D global-scale hybrid simulation model, we investigate the energy spectra of cusp precipitating ions and issues associated with magnetopause reconnection under a southward IMF. Both the spatial and temporal energy ...
Magnetic flux rope formation within a magnetosheath hot flow anomaly
(2020-06-09)
We report observations on 1 March 2004 by the Cluster spacecraft of a hot flow anomaly (HFA) encountered in the dayside magnetosheath near Earth's bow shock. Embedded within the HFA was a magnetic flux rope with a diameter ...
Evolution of CIR storm on 22 July 2009
(2020-06-09)
Global images of ion intensities are deconvolved from TWINS ENA images during the main and recovery phase of a CIR storm on 22 July 2009. The global spatial ion images taken at different times, along with solar wind data, ...
Pickup proton instabilities and scattering in the distant solar wind and the outer heliosheath: Hybrid simulations
(2020-06-09)
The growth of magnetic field fluctuations driven by the injection of pickup ions perpendicular to a background magnetic field in a homogeneous, collisionless plasma is studied using one-dimensional hybrid simulations. ...
Oxygen-hydrogen differentiated observations from TWINS: The 22 July 2009 storm
(2020-06-09)
The 22 July 2009 magnetic storm is the first significant storm during the emergence of the recent prolonged solar cycle minimum. This moderate storm (minimum Dst approximately -78 nT) has received a good deal of attention ...
Comparison of TWINS and THEMIS observations of proton pitch angle distributions in the ring current during the 29 May 2010 geomagnetic storm
(2020-06-09)
The first comparison between energy-dependent ion pitch angle distributions in the ring current deconvolved from Two Wide-angle Imagining Neutral-atom Spectrometers (TWINS) energetic neutral atom (ENA) images and measured ...
Global hybrid simulation of mode conversion at the dayside magnetopause
(2020-06-05)
Mode conversion at the magnetopause has been suggested to lead to the generation of kinetic Alfven waves (KAWs) and effective mass transport from the solar wind into the magnetosphere. To investigate the mode conversion ...
Field line distribution of mass density at geostationary orbit
(2020-06-05)
The distribution of mass density along the field lines affects the ratios of toroidal (azimuthally oscillating) Alfven frequencies, and given the ratios of these frequencies, we can get information about that distribution. ...
Quiet time equatorial mass density distribution derived from AMPTE/CCE and GOES using the magnetoseismology technique
(2020-06-05)
An inversion technique for estimating the properties of the magnetospheric plasma from the harmonic frequencies of the toroidal standing Alfven waves has been used to derive the global equatorial mass density covering ...
Experimental characterization of broadband electrostatic noise due to plasma compression
(2020-06-05)
For a wide variety of laboratory and space plasma environments, theoretical predictions state that plasmas are unstable to inhomogeneous flows over a very broad frequency range. Such sheared flows are generated in the ...
Modeling the loss of inner belt protons by magnetic field line curvature scattering
(2020-06-05)
The sudden loss of energetic protons in the inner radiation belt has been observed during geomagnetic storms. It is hypothesized that this sudden loss occurs because of changes in the geomagnetic field configuration which ...
Signatures of electron Landau resonant interactions with chorus waves from THEMIS observations
(2020-06-05)
Simultaneous observations of electron phase space density (PSD) and chorus waves for more than 4 years by the Time History of Events and Macroscale Interactions during Substorms (THEMIS) are analyzed to identify signatures ...
Investigation of storm time magnetotail and ion injection using three-dimensional global hybrid simulation
(2020-06-05)
Dynamics of the near-Earth magnetotail associated with substorms during a period of extended southward interplanetary magnetic field is studied using a three-dimensional (3-D) global hybrid simulation model that includes ...
The Comprehensive Inner Magnetosphere-Ionosphere Model
(2020-06-05)
Simulation studies of the Earth's radiation belts and ring current are very useful in understanding the acceleration, transport, and loss of energetic particles. Recently, the Comprehensive Ring Current Model (CRCM) and ...
Solar cycle variation of plasma mass density in the outer magnetosphere: Magnetoseismic analysis of toroidal standing Alfven waves detected by Geotail
(2020-06-05)
We study the variation of plasma mass density in the outer magnetosphere over a solar cycle using mass density estimated from the frequency of fundamental toroidal standing Alfven waves observed by the Geotail spacecraft. ...
Whistler anisotropy instabilities as the source of banded chorus: Van Allen Probes observations and particle-in-cell simulations
(2020-06-05)
Magnetospheric banded chorus is enhanced whistler waves with frequencies (r)<(e), where (e) is the electron cyclotron frequency, and a characteristic spectral gap at (r)similar or equal to(e)/2. This paper uses spacecraft ...
Externally driven plasmaspheric ULF waves observed by the Van Allen Probes
(2020-06-05)
We analyze data acquired by the Van Allen Probes on 8 November 2012, during a period of extended low geomagnetic activity, to gain new insight into plasmaspheric ultralow frequency (ULF) waves. The waves exhibited strong ...