Search Publications
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
Magnetospheric location of the equatorward prebreakup arc
Nakamura, R.; Sergeev, V.; Nishimura, Y. +3 more
We address the long-standing problem of the location and origin of the equatorwardmost Pre-Breakup auroral Arc (PBA) by combining energetic particle observations from NOAA Polar Operational Environmental Satellites (POES) overpasses of prebreakup arcs with auroral imaging and magnetospheric observations from the Time History of Events and Macrosca…
Timescales for electron quasi-linear diffusion by parallel and oblique lower-band chorus waves
Artemyev, A. V.; Agapitov, O. V.; Krasnoselskikh, V. V. +2 more
The loss of relativistic electrons from the Earth's radiation belts can be described in terms of the quasi-linear pitch angle diffusion by cyclotron-resonant waves, provided that their frequency spectrum is broad enough. Chorus waves at large wave-normal angles with respect to the magnetic field are often present in CLUSTER and THEMIS measurements…
Observations of the nightside ionosphere of Mars by the Mars Express Radio Science Experiment (MaRS)
Hinson, D. P.; Witasse, O.; Withers, Paul +7 more
The vertical structure of the nightside ionosphere of Mars and its dependence on solar zenith angle are currently poorly determined, as is the importance of two key sources of nightside plasma, electron precipitation and transport of dayside plasma. We examined 37 electron density profiles of the ionosphere of Mars at solar zenith angles of 101°-1…
Energetic particle injections to geostationary orbit: Relationship to flow bursts and magnetospheric state
Nakamura, R.; Sergeev, V. A.; Chernyaev, I. A. +5 more
To address the mechanism and factors controlling the injection of energetic particles to the geostationary orbit (GEO), we analyzed the appearance of injections at the GEO drift shell as observed by LANL spacecraft in the cases where the flow bursts and associated transient dipolarization were detected at the entry to the inner magnetosphere, in t…
Driving Saturn's magnetospheric periodicities from the upper atmosphere/ionosphere: Magnetotail response to dual sources
Kivelson, Margaret G.; Jia, Xianzhe
Despite the high degree of axial symmetry of Saturn's internal magnetic field, rotation-associated periodicities are evident in Saturn's electromagnetic radiation, its magnetic perturbations and its particle populations. Although close to the mean rotation period of the cloud tops, the electromagnetic period drifts slightly over a time scale of ye…