Physics
Scientific paper
Dec 2011
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011agufmsh51d..04r&link_type=abstract
American Geophysical Union, Fall Meeting 2011, abstract #SH51D-04
Physics
[2134] Interplanetary Physics / Interplanetary Magnetic Fields, [2149] Interplanetary Physics / Mhd Waves And Turbulence, [2159] Interplanetary Physics / Plasma Waves And Turbulence, [2164] Interplanetary Physics / Solar Wind Plasma
Scientific paper
The solar wind is hotter than it would be according to an adiabatic fluid expansion, so it must be heated as it moves out from the Sun. The rate of this heating is not determined by kinetic scale processes, but rather by the evolution of the larger scale fields to smaller scales. The generally agreement of a "turbulent cascade rate" and the observed heating has been determined in a number of ways. The driving function for kinetic-scale heating is thus determined by the dynamics of the larger scales. Here we review evidence that the solar wind turbulence is a strongly evolving, with spectral slopes and fluctuation levels that change with distance from the Sun and with the Alfvénicity (cross-helicity) of the fluctuations. Shear represents the dominant energy at the largest scales, and transverse velocity and magnetic fluctuation energy are nearly equipartitioned at these scales. In high cross-helicity regions, spectra are very flat and equipartioned at the smaller scales, but then evolve rapidly through the inner heliosphere, with a different evolution for magnetic and velocity spectra. Less Alfvénic regions are more "evolved" when seen by Helios spacecraft at 0.3 AU. By about 4.5 AU, all the fluctuations studied thus far have reached a Kolmogoroff-like state with a -5/3 slope, but the velocity fluctuations retain lower amplitudes than the magnetic. It is difficult to find evidence of the spatial regions where the dissipation required by the evolution is occurring. The last part of the talk will offer some speculations on what these results mean for turbulence theories and dissipation physics.
No associations
LandOfFree
Evolution of Turbulence and Fluctuations in the Solar Wind as a Function of Distance from the Sun does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Evolution of Turbulence and Fluctuations in the Solar Wind as a Function of Distance from the Sun, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Evolution of Turbulence and Fluctuations in the Solar Wind as a Function of Distance from the Sun will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-881038