Search Publications
Proton velocity distribution in thin current sheets: Cluster observations and theory of transient trajectories
Petrukovich, A. A.; Zelenyi, L. M.; Nakamura, R. +1 more
The structure of thin current sheets in the Earth magnetotail is studied on the basis of 43 crossings by Cluster spacecraft. Current sheet embedding is described as the ratio of the magnitudes of magnetic field at the thin current sheet boundary and in the lobe. This ratio is found to be ∼0.4 on average. The proton population consists of the curre…
Understanding large SEP events with the PATH code: Modeling of the 13 December 2006 SEP event
Verkhoglyadova, O. P.; Cohen, C. M. S.; Mewaldt, R. A. +7 more
The Particle Acceleration and Transport in the Heliosphere (PATH) numerical code was developed to understand solar energetic particle (SEP) events in the near-Earth environment. We discuss simulation results for the 13 December 2006 SEP event. The PATH code includes modeling a background solar wind through which a CME-driven oblique shock propagat…
Magnetic field oscillations near the planetary period in Saturn's equatorial magnetosphere: Variation of amplitude and phase with radial distance and local time
Dougherty, M. K.; Andrews, D. J.; Cowley, S. W. H. +1 more
We present an analysis of the ∼11 h oscillations in Saturn's near-equatorial magnetic field, using Cassini data acquired during 2004-2007. We assume the oscillation period is given by the magnetic phase model derived by Provan et al. (2009) over the same interval, and use this to combine the data to determine the variation of the oscillation ampli…
Cluster observations of simultaneous resonant interactions of ULF waves with energetic electrons and thermal ion species in the inner magnetosphere
Zong, Q. -G.; Reme, H.; Korth, A. +6 more
In this study, we report in situ observations on the simultaneous periodic modulations in the drifting energetic electrons (∼100 keV) and in the bouncing thermal ion species (O+ at ∼4.5 keV and H+ at ∼280 eV) with the same frequency of 3.3 mHz during the storm recovery phase on 21 October 2001. The Cluster fleet was traveling…
Cluster observations of bidirectional beams caused by electron trapping during antiparallel reconnection
Fazakerley, A.; Egedal, J.; Lê, A. +4 more
So-called bidirectional electron beams have been observed by a number of spacecraft missions mainly in the inflow of reconnection regions. Here we show that these beam-like features in the electron distribution function are explained by electron trapping. The trapping is mainly controlled by a positive acceleration potential, Φ$\parallel$
Detection and measurement of ice grains and gas distribution in the Enceladus plume by Cassini's Ion Neutral Mass Spectrometer
Waite, J. H.; Teolis, B. D.; Magee, B. A. +2 more
We report on the measurements of the Cassini Ion Neutral Mass Spectrometer (INMS) of the density and structure of Enceladus' south polar plume during the E3 and E5 flybys on 12 March and 9 October 2008. Using a Monte Carlo simulation, we analyze the dependence of the INMS gas inlet transmittance on spacecraft pointing and the effect on the measure…
A case study of EMIC wave-associated He+ energization in the outer magnetosphere: Cluster and Double Star 1 observations
Sauvaud, J. -A.; Klecker, B.; Kistler, L. M. +3 more
On December 4, 2004, the COmposition and DIstribution Function (CODIF) Analyzer on board the Cluster spacecraft observed a prolonged He+ energization event from 06:00 to 10:30 UT. In this paper, we perform a case study of the event by using in situ plasma and magnetic field measurements from the Cluster and Double Star Program (DSP) Tan…
Latitudinal variations in Saturn's ionosphere: Cassini measurements and model comparisons
Galand, Marina; Moore, Luke; Mendillo, Michael +2 more
We present a study of latitudinal variations in Saturn's ionosphere using Cassini Radio Science Subsystem (RSS) measurements and Saturn-Thermosphere-Ionosphere-Model (STIM) simulations. On the basis of Cassini RSS observations, the peak electron density (NMAX) and the total electron content (TEC) both exhibit a clear increase with latit…
Evolution of the spectrum of solar wind velocity fluctuations from 0.3 to 5 AU
Roberts, D. Aaron
Recent work has shown that at 1 AU from the Sun, the power spectrum of the solar wind magnetic field has the -5/3 spectral slope expected for Kolmogorov turbulence but that the velocity has closer to a -3/2 spectrum. This paper traces the changes in solar wind velocity spectra from 0.3 to 5 AU using data from the Helios and Ulysses spacecraft to s…
Numerical simulation of the 12 May 1997 CME Event: The role of magnetic reconnection
Owens, M. J.; Crooker, N. U.; Gombosi, T. I. +4 more
We perform a numerical study of the evolution of a Coronal Mass Ejection (CME) and its interaction with the coronal magnetic field based on the 12 May 1997, CME event using a global MagnetoHydroDynamic (MHD) model for the solar corona. The ambient solar wind steady-state solution is driven by photospheric magnetic field data, while the solar erupt…