Search Publications
The origin of Saturn's magnetic periodicities: Northern and southern current systems
Cowley, S. W. H.; Southwood, D. J.
The recent survey by Andrews et al. (2012) of the separate northern and southern ~10.7 h periodic magnetic signals in Saturn's magnetosphere limits very much their governing current systems. The existence of signals with pure or close to pure northern or southern periods in respective polar caps taken with the relatively narrow bandwidth of the si…
Oblique reflections in the Mars Express MARSIS data set: Stable density structures in the Martian ionosphere
Gurnett, D. A.; André, M.; Edberg, N. J. T. +6 more
The Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) onboard the European Space Agency's Mars Express (MEX) spacecraft routinely detects evidence of localized plasma density structures in the Martian dayside ionosphere. Such structures, likely taking the form of spatially extended elevations in the plasma density at a given alt…
Interaction of magnetic reconnection and Kelvin-Helmholtz modes for large magnetic shear: 2. Reconnection trigger
Ma, Xuanye; Otto, Antonius; Delamere, Peter A.
A typical property of magnetopause reconnection is a significant perpendicular shear flow due to the fast streaming magnetosheath plasma. Therefore, the magnetopause represents a large magnetic and flow shear boundary during periods of southward interplanetary magnetic field, which can be unstable to Kelvin-Helmholtz (KH) modes and to magnetic rec…
Properties of Kelvin-Helmholtz waves at the magnetopause under northward interplanetary magnetic field: Statistical study
Wang, Chi; Li, Wenya; Tang, Binbin +3 more
We search the plasma and magnetic field data of the Time History of Events and Macroscale Interactions during Substorms (THEMIS) probes B and C during 2008 and 2009 for observation evidences of the Kelvin-Helmholtz instability (KHI). Fourteen KHI events with rolled-up vortices are identified under the northward interplanetary magnetic field (IMF) …
The solar meridional circulation and sunspot cycle variability
Hathaway, D. H.; Upton, L.
We have measured the meridional motions of the magnetic elements in the Sun's surface layers since 1996 and find systematic and substantial variations. In general the meridional flow speed is fast at cycle minima and slow at cycle maxima. We find that these systematic variations are characterized by a weakening of the meridional flow on the polewa…
Effects of a strong ICME on the Martian ionosphere as detected by Mars Express and Mars Odyssey
Gurnett, D. A.; Mitrofanov, I.; Fränz, M. +8 more
We present evidence of a substantial ionospheric response to a strong interplanetary coronal mass ejection (ICME) detected by the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) on board the Mars Express (MEX) spacecraft. A powerful ICME impacted the Martian ionosphere beginning on 5 June 2011, peaking on 6 June, and trailing o…
Properties of dust particles near Saturn inferred from voltage pulses induced by dust impacts on Cassini spacecraft
Gurnett, D. A.; Kempf, S.; Kurth, W. S. +5 more
The Cassini Radio and Plasma Wave Science (RPWS) instrument can detect dust particles when voltage pulses induced by the dust impacts are observed in the wideband receiver. The size of the voltage pulse is proportional to the mass of the impacting dust particle. For the first time, the dust impacts signals measured by dipole and monopole electric …
Electromagnetic ion cyclotron rising tone emissions observed by THEMIS probes outside the plasmapause
Omura, Yoshiharu; Angelopoulos, Vassilis; Shoji, Masafumi +3 more
We report observations of electromagnetic ion cyclotron (EMIC) triggered emissions observed by the Time History of Events and Macroscale Interactions during Substorms (THEMIS) probes outside the plasmasphere. Although these phenomena have recently received much attention because of the possibility of strong interaction with particles, only a few e…
Solar cycle evolution of dipolar and pseudostreamer belts and their relation to the slow solar wind
Owens, M. J.; Crooker, N. U.; Lockwood, M.
Dipolar streamers are coronal structures formed by open solar flux converging from coronal holes of opposite polarity. Thus, the dipolar streamer belt traces the coronal foot point of the heliospheric current sheet, and it is strongly associated with the origin of slow solar wind. Pseudostreamers, on the other hand, separate converging regions of …
Turbulent magnetic field fluctuations in Saturn's magnetosphere
Saur, J.; Alexandrova, O.; von Papen, M.
We analyze the statistical properties of magnetic field fluctuations measured by the Cassini spacecraft inside Saturn's magnetosphere. We introduce Saturn's magnetosphere as a new laboratory for plasma turbulence, where background magnetic field is strong (1 nT<B0≤75 nT), fluctuations are weak (<δB/B> = 0.07), and the ion plasm…