Search Publications
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…
Global network of slow solar wind
Crooker, N. U.; Neugebauer, M.; Antiochos, S. K. +1 more
The streamer belt region surrounding the heliospheric current sheet (HCS) is generally treated as the primary or sole source of the slow solar wind. Synoptic maps of solar wind speed predicted by the Wang-Sheeley-Arge model during selected periods of solar cycle 23, however, show many areas of slow wind displaced from the streamer belt. These area…
Dual periodicities in planetary-period magnetic field oscillations in Saturn's tail
Coates, A. J.; Dougherty, M. K.; Jackman, C. M. +5 more
We examine magnetic field data from 10 apoapsis passes of the Cassini spacecraft during 2006 when the spacecraft explored the midnight and dawn sectors of Saturn's magnetotail to down-tail distances of ∼65 RS (Saturn radius, RS, is 60,268 km). Oscillations in the radial component of the field near the ∼11 hour planetary perio…
Cyclic loss of open solar flux since 1868: The link to heliospheric current sheet tilt and implications for the Maunder Minimum
Owens, M. J.; Lockwood, M.
Open solar flux (OSF) variations can be described by the imbalance between source and loss terms. We use spacecraft and geomagnetic observations of OSF from 1868 to present and assume the OSF source, S, varies with the observed sunspot number, R. Computing the required fractional OSF loss, χ, reveals a clear solar cycle variation, in approximate p…
The first in situ observation of Kelvin-Helmholtz waves at high-latitude magnetopause during strongly dawnward interplanetary magnetic field conditions
ViñAs, A. F.; Goldstein, M. L.; Wang, Y. +3 more
We report the first in situ observation of high-latitude magnetopause (near the northern duskward cusp) Kelvin-Helmholtz waves (KHW) by Cluster on January 12, 2003, under strongly dawnward interplanetary magnetic field (IMF) conditions. The fluctuations unstable to Kelvin-Helmholtz instability (KHI) are found to propagate mostly tailward, i.e., al…
Three-dimensional ray tracing of fast magnetosonic waves
Xiao, Fuliang; Zhou, Qinghua; He, Zhaoguo +1 more
A three dimensional ray tracing of fast magnetosonic (MS) waves is first performed by using a global core density model and a field-aligned density model. Simulating results show that MS waves are primarily confined within a few degrees of the geomagnetic equator due to magnetospheric reflection. MS waves originating from different L-shells on the…