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Dependence of Solar-Wind Power Spectra on the Direction of the Local Mean Magnetic Field
Podesta, J. J.
Wavelet analysis can be used to measure the power spectrum of solar-wind fluctuations along a line in any direction (θ, phi) with respect to the local mean magnetic field B 0. This technique is applied to study solar-wind turbulence in high-speed streams in the ecliptic plane near solar minimum using magnetic field measurements with a c…
Empirical Constraints on Proton and Electron Heating in the Fast Solar Wind
Cranmer, Steven R.; Kasper, Justin C.; Matthaeus, William H. +1 more
We analyze measured proton and electron temperatures in the high-speed solar wind in order to calculate the separate rates of heat deposition for protons and electrons. When comparing with other regions of the heliosphere, the fast solar wind has the lowest density and the least frequent Coulomb collisions. This makes the fast wind an optimal test…
Modulation of Galactic Cosmic Ray Protons and Electrons During an Unusual Solar Minimum
Fichtner, H.; Scherer, K.; Ferreira, S. E. S. +5 more
During the latest Ulysses out-of-ecliptic orbit the solar wind density, pressure, and magnetic field strength have been the lowest ever observed in the history of space exploration. Since cosmic ray particles respond to the heliospheric magnetic field in the expanding solar wind and its turbulence, the weak heliospheric magnetic field as well as t…
The Accuracy of Using the Ulysses Result of the Spatial Invariance of the Radial Heliospheric Field to Compute the Open Solar Flux
Lockwood, M.; Owens, M.
We survey observations of the radial magnetic field in the heliosphere as a function of position, sunspot number, and sunspot cycle phase. We show that most of the differences between pairs of simultaneous observations, normalized using the square of the heliocentric distance and averaged over solar rotations, are consistent with the kinematic "fl…
Energetic Particle Observations and Propagation in the Three-dimensional Heliosphere During the 2006 December Events
Lario, D.; Forsyth, R. J.; Cohen, C. M. S. +9 more
We report observations of solar energetic particles obtained by the HI-SCALE and COSPIN/LET instruments onboard Ulysses during the period of isolated but intense solar activity in 2006 December, in the declining phase of the solar activity cycle. We present measurements of particle intensities and also discuss observations of particle anisotropies…
The Flux of Open and Toroidal Interplanetary Magnetic Field as a Function of Heliolatitude and Solar Cycle
Schwadron, Nathan A.; Smith, Charles W.; Connick, David E.
We examine 45 years of near-Earth interplanetary observations as recorded in the National Space Science Data Center OMNI data set and 18 years of observations by the Ulysses spacecraft. We find that recent claims for a 50+ year low in interplanetary magnetic field intensity are substantiated, that the low flux levels can be attributed to open magn…
Observation of Universality in the Generalized Similarity of Evolving Solar Wind Turbulence as Seen by Ulysses
Carbone, V.; Chapman, S. C.; Leonardis, E. +2 more
We perform statistical analysis of the fluctuating magnetic field observed in-situ by the Ulysses spacecraft, from the perspective of quantitative characterization of the evolving magnetohydrodynamic (MHD) turbulence. We focus on two successive polar passes around solar minimum which provide extended intervals of quiet, fast solar wind at a range …