Search Publications
Cluster observations of the Earth's quasi-parallel bow shock
Dandouras, I.; RèMe, H.; Horbury, T. S. +1 more
Cluster observations of the Earth's quasi-parallel shock are used to investigate properties of the transition and the role of magnetic pulsations in the shock process. We use crossings at small spacecraft separations to show that pulsations grow in only a few seconds. We then use an example when the spacecraft were only a few thousand kilometers a…
Characteristics of middle- to low-latitude Pi2 excited by bursty bulk flows
Zong, Qiugang; Lucek, E.; Zhang, Tielong +13 more
This paper, by using the data of Cluster, TC-1, GOES, and eight ground stations on 22 October 2004, studied the characteristics of low-latitude Pi2s generated by an earthward bursty bulk flow (BBF) in the near-Earth tail plasma sheet. The BBF excited simultaneously two distinct classes of Pi2s: one is long-period Pi2 (90-130 s) and the other is sh…
Validation of a synoptic solar wind model
Gombosi, T. I.; Roussev, I. I.; Cohen, O. +1 more
We present a validation of a three-dimensional magnetohydrodynamic model for the solar corona and the inner heliosphere. We compare the results of the model with long-term satellite data at 1 AU for a 1 year period during solar minimum and another year period of solar maximum. Overall, the model predicts rather well the magnitude of the magnetohyd…
Kinematic properties of solar coronal mass ejections: Correction for projection effects in spacecraft coronagraph measurements
Howard, T. A.; Nandy, D.; Koepke, A. C.
One of the main sources of uncertainty in quantifying the kinematic properties of coronal mass ejections (CMEs) using coronagraphs is the fact that coronagraph images are projected into the sky plane, resulting in measurements which can differ significantly from their actual values. By identifying solar surface source regions of CMEs using X-ray a…
Superdiffusive transport of electrons accelerated at corotating interaction regions
Zimbardo, Gaetano; Perri, Silvia
Energetic particles in the solar wind are accelerated at interplanetary shock waves associated with corotating interaction regions (CIRs) and propagate in the presence of a spectrum of magnetic turbulence, which causes pitch angle scattering upstream of the shock. Besides normal diffusive transport, we study the possibility of superdiffusive trans…
Observations of chorus at Saturn using the Cassini Radio and Plasma Wave Science instrument
Gurnett, D. A.; Dougherty, M. K.; Hospodarsky, G. B. +4 more
Observations at Saturn of whistler mode chorus emissions have been obtained by the Cassini Radio and Plasma Wave Science instrument. Data from the first 45 orbits are analyzed, and the characteristics of the chorus emissions are discussed. Wave normal and Poynting vector measurements from the five-channel waveform receiver are used to examine the …
Magnetic field structure of Saturn's dayside magnetosphere and its mapping to the ionosphere: Results from ring current modeling
Dougherty, M. K.; Cowley, S. W. H.; Bunce, E. J. +1 more
Ring current modeling in Saturn's magnetosphere using Pioneer-11, Voyager, and Cassini data has shown that the size and strength of the current system grows with the extension of the magnetosphere, governed by the solar wind dynamic pressure. Here we show that the consequent middle magnetosphere field is quasi-dipolar in form when the magnetospher…
First results from the Cassini radio occultations of the Titan ionosphere
French, Richard G.; Flasar, F. Michael; Marouf, Essam A. +10 more
The first four sets of radio occultations of the Titan's ionosphere were obtained by the Cassini spacecraft between March 2006 and May 2007. These occultations occurred at middle and high latitudes, at solar zenith angles from about 86° to 96°. The main ionospheric peak was seen, as expected from modeling and previous observations, near 1200 km, w…
Discontinuity in Jupiter's main auroral oval
Krupp, N.; Woch, J.; Bonfond, B. +3 more
On the basis of a series of FUV Hubble Space Telescope images obtained between 1997 and 2007 it is shown that there is a segment of the main auroral oval where the emission drops significantly from a few hundreds to a few tens of kiloRayleigh, forming a discontinuity in the oval. It is shown that the discontinuity is present in both hemispheres an…
Modeling of Saturn kilometric radiation arcs and equatorial shadow zone
Cecconi, B.; Lamy, L.; Zarka, P. +2 more
Accelerated electrons gyrating around Saturn's auroral (high latitude) magnetic field lines generate the intense Saturnian kilometric radiation (SKR). This radio emission is thought to be generated via the cyclotron maser instability (CMI) that predicts a strong anisotropy of the beaming pattern of the emission. Resulting visibility effects were s…