Search Publications
The Interstellar H Flow: Updated Analysis of SOHO/SWAN Data
Bertaux, Jean-Loup; Lallement, Rosine; Lamy, Philippe +4 more
We update two kinds of results obtained with the SWAN instrument on board SOHO. First, we use H cell data recorded in 2001 and derive the H flow direction in the same way the study was done at solar minimum. We again compare with the Helium flow direction and doing so correct for the coordinate system change between the Ulysses and SOHO missions. …
Self-Reformation of the Quasi-Perpendicular Shock: CLUSTER Observations
Dandouras, I.; Génot, V.; Lembège, B. +5 more
Among several mechanisms issued from simulation and theoretical studies proposed to account for the nonstationarity of quasi-perpendicular supercritical shocks, one process-the so-called self-reformation-driven by the accumulation of reflected ions in the foot has been intensively analyzed with simulations. Present results based on experimental CL…
Whistler Waves Driven by Anisotropic Strahl Velocity Distributions: Cluster Observations
Gurgiolo, C.; Goldstein, M. L.; Nieves-Chinchilla, T. +2 more
Observed properties of the strahl using high resolution 3D electron velocity distribution data obtained from the Cluster/PEACE experiment are used to investigate its linear stability. An automated method to isolate the strahl is used to allow its moments to be computed independent of the solar wind core+halo. Results show that the strahl can have …
Solar wind turbulent spectrum from MHD to electron scales
Saur, J.; Alexandrova, O.; Schwartz, S. J. +5 more
Turbulent spectra of magnetic fluctuations in the free solar wind are studied from MHD to electron scales using Cluster observations. We discuss the problem of the instrumental noise and its influence on the measurements at the electron scales. We confirm the presence of a curvature of the spectrum ~expkρe over the broad frequency range…
Heliospheric Energetic Particle Reservoirs: Ulysses and ACE 175-315 keV Electron Observations
Lario, D.
Heliospheric energetic particle reservoirs are usually observed in the decay phase of large solar energetic particle (SEP) events when particle intensities measured by widely separated spacecraft (in longitude, latitude and radial distance) present comparable intensities (within a factor of 2-3) that evolve similarly in time. We use near-relativis…
Analysis of waves surrounding foreshock cavitons
Kajdič, Primož; Russell, Christopher T.; Blanco-Cano, Xochitl +1 more
Cavitons have been recently discovered in the Earth's foreshock. Foreshock cavitons have first been predicted by global hybrid simulations and later structures with similar properties were discovered in observational data from the Cluster mission. Cavitons are observed as simultaneous depressions of the magnitude of the magnetic field and plasma d…
Ulysses Observations of the Properties of Multiple Ion Beams in the Solar Wind
Goldstein, B. E.; Neugebauer, M.; Zhou, X. -Y.
Properties of multiple ion beams in the solar wind beyond 1 AU as observed by the SWOOPS experiment on Ulysses are discussed. The solar wind proton distributions are approximated by a two beam bi-Maxwellian model. The slower outward traveling beam typically comprises the majority of the solar wind density. Differential streaming between the slower…
Role of latitude of source region in Solar Energetic Particle events
Dalla, S.; Agueda, N.
Solar Energetic Particle (SEP) measurements from the Ulysses spacecraft have shown that the latitudinal separation between the parent solar flare and the nominal footpoint of the detecting spacecraft is an important parameter in ordering characteristics of the observed time-intensity profiles during SEP events. In this study, we consider data from…
Transient Phenomena in the Distant Solar Wind and in the Heliosheath
McComas, D. J.; Pogorelov, N. V.; Burlaga, L. F. +6 more
The difference in the heliocentric distances at which the Voyager 1 and Voyager 2 spacecraft crossed the termination shock (TS) is likely due to a combination of the heliospheric asymmetry caused by the interstellar magnetic field (ISMF) and time-dependent boundary conditions at the Sun. We analyze both effects numerically. It is shown that an inc…
Velocity Distributions and Proton Beam Production in the Solar Wind
Voitenko, Yuriy; Pierrard, Viviane
Helios, Ulysses, and Wind spacecraft have observed the velocity distribution functions (VDFs) of solar wind particles deviating significantly from Maxwellians. We review recent models using different approximations and mechanisms that determine various observed characteristics of the VDFs for the electrons, protons and minor ions. A new generation…