Search Publications
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…
Wave-particle interactions in the equatorial source region of whistler-mode emissions
Gurnett, D. A.; Pickett, J. S.; Santolík, O. +8 more
Wave-particle interactions can play a key role in the process of transfer of energy between different electron populations in the outer Van Allen radiation belt. We present a case study of wave-particle interactions in the equatorial source region of whistler-mode emissions. We select measurements of the Cluster spacecraft when these emissions are…
Limitations of multispacecraft data techniques in measuring wave number spectra of space plasma turbulence
Belmont, G.; Sahraoui, F.; Rezeau, L. +1 more
Unambiguous determination of spatial properties of space plasma turbulence from temporal measurements has been one of the major goals of the Cluster mission. For that purpose, techniques, such as the k filtering, have been developed. Such multipoint measurement techniques combine several time series recorded simultaneously at different points in s…
Pitch angle transport of electrons due to cyclotron interactions with the coherent chorus subelements
Lakhina, G. S.; Tsurutani, B. T.; Verkhoglyadova, O. P. +1 more
Chorus is a right-hand, circularly-polarized electromagnetic plane wave. Dayside chorus is a bursty emission composed of rising frequency “elements” with duration of ∼0.1 to 1.0 s. Each element is composed of coherent subelements with durations of ∼1 to 100 ms or more. Due to the coherent nature of the chorus subelements/wave packets, energetic el…
Observations of the relationship between frequency sweep rates of chorus wave packets and plasma density
Gurnett, D. A.; Pickett, J. S.; Demekhov, A. G. +8 more
Chorus emissions are generated by a nonlinear mechanism involving wave-particle interactions with energetic electrons. Discrete chorus wave packets are narrowband tones usually rising (sometimes falling) in frequency. We investigate frequency sweep rates of chorus wave packets measured by the Wideband data (WBD) instrument onboard the Cluster spac…
Magnetopause oscillations near the planetary period at Saturn: Occurrence, phase, and amplitude
Coates, A. J.; Andrews, D. J.; Cowley, S. W. H. +2 more
Using magnetic field and plasma electron data from ∼40 Cassini orbits that crossed Saturn's magnetopause during 2004-2007, we make a first systematic study of the magnetopause oscillations that are related to the oscillations in the magnetic field and plasma inside the magnetosphere near the ∼11 h planetary rotation period, here termed the magneto…
THEMIS observations of substorms on 26 February 2008 initiated by magnetotail reconnection
Russell, C. T.; Wei, Y.; Glassmeier, K. -H. +25 more
On 26 February 2008, the THEMIS satellites observed two substorms that occurred at about 0405 and 0455 UT. Angelopoulos et al. (2008) made a comprehensive study of the second event. In this paper we display detailed features of the two substorms with emphasis on the first. In both substorms, a distinct auroral intensification occurred during the e…