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. …
Heliospheric evolution of solar wind small-scale magnetic flux ropes
Moldwin, M. B.; Cartwright, M. L.
We present results from the first comprehensive small-scale flux rope survey between 0.3 and 5.5 AU using the Helios 1, Helios 2, IMP 8, Wind, ACE, and Ulysses spacecrafts to examine their occurrence rate, properties, and evolution. Small-scale flux ropes are similar to magnetic clouds and can be modeled as a constant-alpha, force-free, cylindrica…
Observations of Anisotropic Scaling of Solar Wind Turbulence
Wu, D. J.; Luo, Q. Y.
Using high-speed solar wind data recorded by the Ulysses spacecraft, we investigate and estimate the anisotropic inertial range scaling of the interplanetary magnetic field. We apply the method of the magnetic structure function (MSF), Sn (τ) = lang|b(t + τ) - b(t)| n rang vprop τζ(n), to analyze the scaling of sol…
Earth-Moon-Mars Radiation Environment Module framework
Schwadron, N. A.; Posner, A.; Dayeh, M. A. +11 more
We are preparing to return humans to the Moon and setting the stage for exploration to Mars and beyond. However, it is unclear if long missions outside of low-Earth orbit can be accomplished with acceptable risk. The central objective of a new modeling project, the Earth-Moon-Mars Radiation Exposure Module (EMMREM), is to develop and validate a nu…
The reversal of the rotational modulation rates of the north and south components of Saturn kilometric radiation near equinox
Gurnett, D. A.; Persoon, A. M.; Kurth, W. S. +5 more
It has been known for many years that Saturn emits intense radio emissions at kilometer wavelengths and that this radiation is modulated by the rotation of the planet at a rate that varies slowly on time scales of years. Recently it has been shown that the radio emission consists of two components that have different rotational modulation rates, o…
Mapping the Distribution of Electron Temperature and Fe Charge States in the Corona with Total Solar Eclipse Observations
Rušin, V.; Druckmüller, M.; Esser, R. +7 more
The inference of electron temperature from the ratio of the intensities of emission lines in the solar corona is valid only when the plasma is collisional. Once collisionless, thermodynamic ionization equilibrium no longer holds, and the inference of an electron temperature and its gradient from such measurements is no longer valid. At the helioce…
Oxygen flux in the solar wind: Ulysses observations
Zurbuchen, Thomas H.; von Steiger, Rudolf; McComas, David J.
We use the complete set of Ulysses solar wind data to conduct a comprehensive determination of the oxygen flux in relation to the proton flux in the solar wind during a wide range of solar activity levels. The data cover the heliosphere between 1.3 and 5.4 AU and, due to the unique orbit of Ulysses, all of the heliographic latitudes within ±80°. W…
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…
On the Relative Constancy of the Solar Wind Mass Flux at 1 AU
Wang, Y. -M.
Employing solar wind measurements from the Advanced Composition Explorer and Ulysses, photospheric magnetic data, and conservation laws along open field lines, we confirm that the energy and mass flux densities at the Sun increase roughly linearly with the footpoint field strength, B 0. This empirical result has a number of important ph…
First results from the Venetia Burney Student Dust Counter on the New Horizons mission
James, David; Horányi, Mihály; Poppe, Andrew +1 more
The Venetia Burney Student Dust Counter (SDC) onboard the New Horizons mission is an impact-based dust detector designed to map the size and spatial variability of the interplanetary dust population throughout the solar system. SDC consists of fourteen permanently polarized polyvinylidene fluoride detectors that register a charge upon impact by hy…