HR: 14:00h
AN: SH23A-11    [Abstracts]
TI: Evolution of the spectrum of velocity and magnetic fluctuations in the solar wind
AU: * Roberts, D A
EM: aaron.roberts@nasa.gov
AF: NASA GSFC, Code 672, Greenbelt, MD 20771, United States
AB: Recent work has shown that at 1 AU from the Sun the power spectrum of the magnetic field has the -5/3 spectral slope expected for Kolmogorov turbulence, but that the velocity has closer to a -3/2 spectrum. The latter slope is predicted for magnetically dominated turbulence, but if this were the case one might expect that the magnetic spectrum would be most likely to have the -3/2 slope. An alternative perspective is that the -3/2 is accidental and transient, and that the -5/3 slope is the eventual state of the all the fluctuations. Here we present spectra from Helios, Wind, Voyager, and other spacecraft to support the evolutionary view. If this is the correct interpretation of the results, then the question still arises of why the velocity evolves at a different rate from the magnetic field. This talk will not answer this question, but will begin to quantify the obersvational evidence.
DE: 2134 Interplanetary magnetic fields
DE: 2159 Plasma waves and turbulence
DE: 2164 Solar wind plasma
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2007 Joint Assembly