Search Publications
Global model of lower band and upper band chorus from multiple satellite observations
Meredith, Nigel P.; Horne, Richard B.; Thorne, Richard M. +4 more
Gyroresonant wave particle interactions with whistler mode chorus play a fundamental role in the dynamics of the Earth's radiation belts and inner magnetosphere, affecting both the acceleration and loss of radiation belt electrons. Knowledge of the variability of chorus wave power as a function of both spatial location and geomagnetic activity, re…
Pitch angle distribution of suprathermal electrons behind dipolarization fronts: A statistical overview
Daly, P. W.; André, M.; Vaivads, A. +5 more
We examine the pitch angle distribution (PAD) of suprathermal electrons (>40 keV) inside the flux pileup regions (FPRs) that are located behind the dipolarization fronts (DFs), in order to better understand the particle energization mechanisms operating therein. The 303 earthward-propagating DFs observed during 9 years (2001-2009) by Cluster 1 …
Nonlinear pitch angle scattering of relativistic electrons by EMIC waves in the inner magnetosphere
Omura, Yoshiharu; Zhao, Qinghua
We derive the second-order resonance condition for interaction between a relativistic electron and a coherent Electromagnetic Ion Cyclotron (EMIC) wave with a variable frequency. We perform test particle simulations of relativistic electrons interacting with EMIC waves with a fixed frequency and a rising-tone frequency such as EMIC triggered emiss…
Magnetospheric configuration and dynamics of Saturn's magnetosphere: A global MHD simulation
Hansen, Kenneth C.; Gombosi, Tamas I.; Kivelson, Margaret G. +4 more
We investigate the solar wind interaction with Saturn's magnetosphere by using a global magnetohydrodynamic simulation driven by an idealized time-varying solar wind input that includes features of Corotating Interaction Regions typically seen at Saturn. Our model results indicate that the compressibility of Saturn's magnetosphere is intermediate …
Remote and in situ observations of an unusual Earth-directed coronal mass ejection from multiple viewpoints
Anderson, B. J.; Szabo, A.; Nieves-Chinchilla, T. +5 more
During June 16-21, 2010, an Earth-directed coronal mass ejection (CME) event was observed by instruments onboard STEREO, SOHO, MESSENGER and Wind. This event was the first direct detection of a rotating CME in the middle and outer corona. Here, we carry out a comprehensive analysis of the evolution of the CME in the interplanetary medium comparing…
Magnetosheath pressure pulses: Generation downstream of the bow shock from solar wind discontinuities
Eastwood, J. P.; Horbury, T. S.; Archer, M. O.
We present multipoint Time History of Events and Macroscale Interactions during Substorms (THEMIS) observations of transient dynamic pressure pulses in the magnetosheath 3-10 times the background in amplitude, due to enhancements in both the ion density and velocity. Their spatial dimensions are of the order of ∼1 RE parallel to the flo…
Driving Saturn's magnetospheric periodicities from the upper atmosphere/ionosphere
Gombosi, Tamas I.; Kivelson, Margaret G.; Jia, Xianzhe
Saturn's magnetospheric structure and the intensity of radio frequency emissions from its immediate surroundings are modulated at close to the planet's rotation period. Analogous rotation-modulated variations at Jupiter are readily interpreted as effects of the non-axisymmetric intrinsic magnetic field. At Saturn, to the contrary, the high level o…
Planetary period oscillations in Saturn's magnetosphere: Evolution of magnetic oscillation properties from southern summer to post-equinox
Dougherty, M. K.; Lamy, L.; Andrews, D. J. +3 more
We investigate the evolution of the properties of planetary period magnetic field oscillations observed by the Cassini spacecraft in Saturn's magnetosphere over the interval from late 2004 to early 2011, spanning equinox in mid-2009. Oscillations within the inner quasi-dipolar region (L ≤ 12) consist of two components of close but distinct periods…
The location of reconnection at the magnetopause: Testing the maximum magnetic shear model with THEMIS observations
Fuselier, S. A.; Phan, T. D.; Trattner, K. J. +1 more
Reconnection at the Earth's magnetopause is the mechanism by which magnetic fields in different regions change topology to create open magnetic field lines that allow energy and momentum to flow into the magnetosphere. One of the long-standing open questions about magnetic reconnection is the location of the reconnection line. There are two reconn…
Charged nanograins in the Enceladus plume
Lewis, G. R.; Coates, A. J.; Thomsen, M. F. +12 more
There have been three Cassini encounters with the south-pole eruptive plume of Enceladus for which the Cassini Plasma Spectrometer (CAPS) had viewing in the spacecraft ram direction. In each case, CAPS detected a cold dense population of heavy charged particles having mass-to-charge (m/q) ratios up to the maximum detectable by CAPS (∼104