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 …
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…
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 …
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…
Ulysses Observations of Magnetic Waves Due to Newborn Interstellar Pickup Ions. II. Application of Turbulence Concepts to Limiting Wave Energy and Observability
Isenberg, Philip A.; Murphy, Neil; Cannon, Bradford E. +4 more
The low-frequency magnetic waves that arise from the isotropization of newborn interstellar pickup ions (PUIs) are reasonably well described by linear and quasi-linear kinetic theory in so far as those theories predict the wave frequency and polarization in the spacecraft frame. Those theories fail to describe the scarce observability of the waves…
Cosmic Ray Transport in Heliospheric Magnetic Structures. I. Modeling Background Solar Wind Using the CRONOS Magnetohydrodynamic Code
Fichtner, H.; Heber, B.; Kühl, P. +4 more
The transport of energetic particles such as cosmic rays is governed by the properties of the plasma being traversed. While these properties are rather poorly known for galactic and interstellar plasmas due to the lack of in situ measurements, the heliospheric plasma environment has been probed by spacecraft for decades and provides a unique oppor…
Neutral Interstellar Helium Parameters Based on Ulysses/GAS and IBEX-Lo Observations: What are the Reasons for the Differences?
Wood, B. E.; Katushkina, O. A.; Izmodenov, V. V. +1 more
Recent analysis of the interstellar helium fluxes measured in 2009-2010 at Earth's orbit by the Interstellar Boundary Explorer (IBEX) has suggested that the interstellar velocity (both direction and magnitude) is inconsistent with that derived previously from Ulysses/GAS observations made in the period from 1990 to 2002 at 1.5-5.5 AU from the Sun.…
Charge State Evolution in the Solar Wind. III. Model Comparison with Observations
Lepri, S. T.; Zurbuchen, T. H.; Fisk, L. A. +3 more
We test three theoretical models of the fast solar wind with a set of remote sensing observations and in-situ measurements taken during the minimum of solar cycle 23. First, the model electron density and temperature are compared to SOHO/SUMER spectroscopic measurements. Second, the model electron density, temperature, and wind speed are used to p…
Plasma Flows in the Heliosheath along the Voyager 1 and 2 Trajectories due to Effects of the 11 yr Solar Cycle
Toth, G.; Richardson, J. D.; Opher, M. +2 more
We investigate the role of the 11 yr solar cycle variations in the solar wind (SW) parameters on the flows in the heliosheath using a new three-dimensional time-dependent model of the interaction between the SW and the interstellar medium. For boundary conditions in the model we use realistic time and the latitudinal dependence of the SW parameter…