Search Publications
Spectra of polar heliospheric fields and implications for field structure
Giacalone, Joe; Jokipii, J. R.; Goldstein, Melvyn L. +2 more
The predictions of the ``Fisk'' model for a peak at the equatorial solar rotation frequency in the spectrum of the latitudinal component of the heliospheric magnetic field were found to give values significantly larger than those observed. The observed values were statistically the same as observed in the ecliptic and were consistent with random f…
Radio tracking of the interplanetary coronal mass ejection driven shock crossed by Ulysses on 10 May 2001
MacDowall, R. J.; Hoang, S.; Lacombe, C. +1 more
We report on the detection of type II radio emission which was observed for more than a day prior to the arrival of an interplanetary shock at Ulysses. We use local spectral emission peaks, computerized from time-averaged intensity spectra of the type II burst, to track the associated emitting shock. In the spectrogram plotted as a function of tim…
Spectral features of SKR observed by Cassini/RPWS: Frequency bandwidth, flux density and polarization
Lecacheux, Alain; Boudjada, Mohammed Y.; Galopeau, Patrick H. M.
We report on an analysis about the spectral shape of the Saturnian kilometric radiation (SKR) recorded by the RPWS/HFR experiment onboard the Cassini spacecraft. The SKR envelope is found to be very variable in timescales covering a large range, from hours to days. Despite this change, we proceed to a classification of the shape in the frequency r…
Simultaneous observations of magnetotail reconnection and bright X-ray aurora on 2 October 2002
RèMe, H.; Lucek, E. A.; Mouikis, C. +9 more
We present simultaneous Cluster and Polar X-ray and UVI observations on 2 October 2002, when Cluster observed a magnetic reconnection diffusion region at Xgse = -16.6 Re. At the same time a bright auroral feature appeared at the footpoint of the magnetic field line connecting the ionosphere and the diffusion region. However, we found that the elec…
Low-frequency waves in the foreshock of Saturn: First results from Cassini
Dougherty, M. K.; Hospodarsky, G. B.; Thomsen, M. +4 more
We present the first characterization of low-frequency upstream waves associated with Saturn's foreshock from observations by the Cassini spacecraft. A classification based on their frequency in the spacecraft frame (s/c) yields two groups: (1) a large majority of waves with frequencies below the local proton cyclotron frequency ΩH+ and…
Energetic particles during the first and third Ulysses southern high-latitude excursions: Probing global corotating interaction region structure beyond 5 AU
Lario, D.; Roelof, E. C.
We analyze energetic particle observations during the first and third ascents of Ulysses to the southern regions of the heliosphere. The first high-latitude excursion occurred in the declining phase of solar cycle 22, while the third occurred in a later phase of solar cycle 23. In contrast to the long-lived and well-defined ~26-day recurrent inten…
Ion thermalization and wave excitation downstream of Earth's bow shock: A theory for Cluster observations of He2+ acceleration
Lee, Martin A.; Kucharek, Harald; Liu, Yong C. -M. +1 more
It has been well documented that the plasma immediately downstream of Earth's quasi-perpendicular bow shock, which consists of reflected protons and directly transmitted ions with large temperature anisotropies (T⊥/Tz), is unstable to the excitation of ion cyclotron waves. These waves in turn scatter the protons and ions to m…
Reconstruction of the reconnection rate from Cluster measurements: Method improvements
Farrugia, C. J.; Penz, T.; Nakamura, R. +7 more
A remote-sensing method for reconstructing the reconnection rate and the location of X-line from single-spacecraft observations developed recently is extended to a compressible plasma and an asymmetric magnetic field configuration. The method is based on the two-dimensional analytical model of time-dependent Petschek-type magnetic reconnection. Th…
A three-dimensional kinetic-fluid numerical code to study the equilibrium structure of the magnetotail: The role of electrons in the formation of the bifurcated current sheet
Veltri, P.; Zimbardo, G.; Greco, A. +1 more
In this work we present a new stationary three-dimensional kinetic-fluid code with ions represented by particles and electrons by a massless fluid. The magnetotail current sheet is modeled as a magnetic field reversal with a normal magnetic field component Bn. A cross tail electric field Ey is included. An ion test particle s…
Polarization measurements of Saturn Electrostatic Discharges with Cassini/RPWS below a frequency of 2 MHz
Gurnett, D. A.; Kurth, W. S.; Fischer, G. +2 more
Early in 2006 the RPWS (Radio and Plasma Wave Science) instrument and the ISS (Imaging Science Subsystem) onboard the Cassini spacecraft detected a lightning storm on Saturn that lasted for about one month. The RPWS measured the so-called SEDs (Saturn Electrostatic Discharges), which are high frequency radio signals produced by lightning discharge…