Search Publications
Radial Dependence of the Frequency Break between Fluid and Kinetic Scales in the Solar Wind Fluctuations
Bruno, R.; Trenchi, L.
We investigate the radial dependence of the spectral break separating the inertial from the dissipation range in power density spectra of interplanetary magnetic field fluctuations, between 0.42 and 5.3 AU, during radial alignments between MESSENGER and WIND for the inner heliosphere and between WIND and ULYSSES for the outer heliosphere. We found…
Three-fluid, Three-dimensional Magnetohydrodynamic Solar Wind Model with Eddy Viscosity and Turbulent Resistivity
Matthaeus, William H.; Goldstein, Melvyn L.; Usmanov, Arcadi V.
We have developed a three-fluid, three-dimensional magnetohydrodynamic solar wind model that incorporates turbulence transport, eddy viscosity, turbulent resistivity, and turbulent heating. The solar wind plasma is described as a system of co-moving solar wind protons, electrons, and interstellar pickup protons, with separate energy equations for …
Warm Breeze from the Starboard Bow: a New Population of Neutral Helium in the Heliosphere
Wurz, P.; McComas, D. J.; Fuselier, S. A. +9 more
We investigate the signals from neutral helium atoms observed in situ from Earth orbit in 2010 by the Interstellar Boundary Explorer (IBEX). The full helium signal observed during the 2010 observation season can be explained as a superposition of pristine neutral interstellar He gas and an additional population of neutral helium that we call the W…
Physical Interpretation of the Angle-dependent Magnetic Helicity Spectrum in the Solar Wind: The Nature of Turbulent Fluctuations near the Proton Gyroradius Scale
Klein, Kristopher G.; TenBarge, Jason M.; Howes, Gregory G. +1 more
Motivated by recent observations of distinct parallel and perpendicular signatures in magnetic helicity measurements segregated by wave period and angle between the local magnetic field and the solar wind velocity, this paper undertakes a comparison of three intervals of Ulysses data with synthetic time series generated from a physically motivated…
Neutral interstellar He parameters in front of the heliosphere 1994-2007
Bzowski, M.; Witte, M.; Banaszkiewicz, M. +3 more
Context. A recent analysis of IBEX measurements of the neutral interstellar He flux showed that the inflow velocity vector is different from the results of an earlier analysis of observations from the GAS instrument onboard Ulysses. A recently published compilation of published results on the helium inflow direction from the past ~40 years suggest…
Time-Dependent Modulation of Cosmic Rays in the Heliosphere
Ferreira, S. E. S.; Potgieter, M. S.; Manuel, R.
The time-dependent modulation of galactic cosmic rays in the heliosphere is studied by computing intensities using a time-dependent modulation model. By introducing recent theoretical advances in the transport coefficients in the model, computed intensities are compared with Voyager 1, International Monitoring Platform (IMP) 8, and Ulysses proton …
The Solar Wind Neon Abundance Observed with ACE/SWICS and Ulysses/SWICS
Landi, Enrico; Zurbuchen, Thomas H.; von Steiger, Rudolf +5 more
Using in situ ion spectrometry data from ACE/SWICS, we determine the solar wind Ne/O elemental abundance ratio and examine its dependence on wind speed and evolution with the solar cycle. We find that Ne/O is inversely correlated with wind speed, is nearly constant in the fast wind, and correlates strongly with solar activity in the slow wind. In …
Solar cycle evolution of dipolar and pseudostreamer belts and their relation to the slow solar wind
Owens, M. J.; Crooker, N. U.; Lockwood, M.
Dipolar streamers are coronal structures formed by open solar flux converging from coronal holes of opposite polarity. Thus, the dipolar streamer belt traces the coronal foot point of the heliospheric current sheet, and it is strongly associated with the origin of slow solar wind. Pseudostreamers, on the other hand, separate converging regions of …
Identification of Interplanetary Coronal Mass Ejections at Ulysses Using Multiple Solar Wind Signatures
Richardson, I. G.
Previous studies have discussed the identification of interplanetary coronal mass ejections (ICMEs) near the Earth based on various solar wind signatures. In particular, methods have been developed of identifying regions of anomalously low solar wind proton temperatures (Tp) and plasma compositional anomalies relative to the composition…
Ulysses Observations of Magnetic Waves due to Newborn Interstellar Pickup Ions. I. New Observations and Linear Analysis
Isenberg, Philip A.; Murphy, Neil; Cannon, Bradford E. +3 more
We have examined Ulysses magnetic field data using dynamic spectrogram techniques that compute wave amplitude, polarization, and direction of propagation over a broad range of frequencies and time. Events were identified that showed a strong polarization signature and an enhancement of power above the local proton gyrofrequency. We perform a stati…