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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…
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equilibrium no longer holds, and the inference of an electron temperature and its gradient from such measurements is no longer valid.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…
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…
Stationarity in Solar Wind Flows
Perri, S.; Balogh, A.
By using single-point measurements in space physics it is possible to study a phenomenon only as a function of time. This means that we cannot have direct access to information about spatial variations of a measured quantity. However, the investigation of the properties of turbulence and of related phenomena in the solar wind widely makes use of a…
Radial Evolution of Solar Wind Turbulence during Earth and Ulysses Alignment of 2007 August
Balogh, A.; Bavassano, B.; Bruno, R. +4 more
At the end of 2007 August, during the minimum of solar cycle 23, a lineup of Earth and Ulysses occurred, giving the opportunity to analyze, for the first time, the same plasma sample at different observation points, namely at 1 and 1.4 AU. In particular, it allowed us to study the radial evolution of solar wind turbulence typical of fast wind stre…
On the Constancy of the Electron Temperature in the Expanding Corona Throughout Solar Cycle 23
Morgan, Huw; Habbal, Shadia Rifai; Druckmüller, Miloslav +1 more
A recent analysis of Fe emission lines observed during the total solar eclipses of 2006 March 29 and 2008 August 1 established the first empirical link between the electron temperature in the expanding corona and Fe charge states measured in interplanetary space. In this Letter, we use this link to infer this temperature throughout solar cycle 23 …
Demonstrations that the Solar Wind is Not Accelerated By Waves or Turbulence
Roberts, D. Aaron
The present work uses observations and theoretical considerations to provide both qualitative and quantitative arguments that hydromagnetic waves, whether turbulent or not, cannot produce the acceleration of the fast solar wind and the related heating of the open solar corona. Waves do exist, and can play a role in the differential heating and acc…
Plasma Near the Heliosheath: Observations and Interpretations
Wang, C.; Richardson, J. D.
Voyager 2 (V2) has observed heliosheath plasma since 2007 August. The plasma flux decreases by 25% before the termination shock (TS), then, as V2 moved into the heliosheath, the plasma density, temperature, and flux all decreased by an additional factor of 2. We suggest three effects combine to cause these decreases. (1) V2 moved into the lower-fl…
Characterization of Transitions in the Solar Wind Parameters
Perri, S.; Balogh, A.
The distinction between fast and slow solar wind streams and the dynamically evolved interaction regions is reflected in the characteristic fluctuations of both the solar wind and the embedded magnetic field. High-resolution magnetic field data from the Ulysses spacecraft have been analyzed. The observations show rapid variations in the magnetic f…
The Global Solar Wind Between 1 AU and the Termination Shock
Whang, Y. C.
This paper studies the global solar wind between 1 AU and the termination shock, taking into account the highly latitude dependent solar wind at the 1 AU boundary and the ionization of interstellar neutral hydrogen. A system of two-fluid magnetohydrodynamics equations governs the flow of solar wind plasma; the conditions of the solar wind at 1 AU …