Physics – Plasma Physics
Scientific paper
Dec 2010
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010agufmsh41b1803a&link_type=abstract
American Geophysical Union, Fall Meeting 2010, abstract #SH41B-1803
Physics
Plasma Physics
[7863] Space Plasma Physics / Turbulence
Scientific paper
Turbulent cascade and its dissipation in collisionless space plasmas is a matter of debates for the last few decades. We study the solar wind magnetic turbulence from MHD to electron scales for quasi-perpendicular flow-to-field angles, that gives us measurement of k⊥ spectra under the assumption of validity of the Taylor hypothesis. In the recent works of Alexandrova et al. [2009, 2010], Cluster measurements for different plasma conditions have been used to show that the turbulent spectrum in the free solar wind has a quasi-universal form: at MHD scales, a Kolmogorov's law ˜ k-5/3 was found, in agreement with previous observations. At scales smaller than the ion characteristic scales, a k-2.7 law was observed (in the frequency domain this spectrum covers ˜ [1,10] Hz range). The transition from one power-law to the other, that corresponds to ˜ [0.1,1] Hz, was found to be not universal: the spectral index varies here between -2 and -4. At scales kρ e ˜ (0.1-1), where ρ e is the electron gyroradius, (i.e. for f>10 Hz) the magnetic spectrum was found to be curved, indicating the onset of dissipation. The most intense spectra, resolved up to 100 Hz, could be approximated by an exponential law ˜ \exp (-√ {kρ e}). This is the first observation of an exponential magnetic spectrum in space plasmas. We showed that ρ e controls the turbulence level, as the dissipation scale does in the neutral fluid turbulence. These results were obtained considering 7 time periods in the free solar wind. Here we use a data set of 140 time periods to verify our results at electron scales. A comparison with the observations at the electron scales in the electron foreshock of the Earth's bow-shock reported by Sahraoui et al. [2009] will be also presented.
Alexandrova Olga
Lacombe Catherine
Maksimovic Milan
Mangeney Andre
Mitchell Jeffrey J.
No associations
LandOfFree
Solar wind magnetic turbulence at electron scales 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 Solar wind magnetic turbulence at electron scales, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Solar wind magnetic turbulence at electron scales will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1510317