| Autor: |
Voitenko, Yuriy, De Keyser, Johan |
| Rok vydání: |
2016 |
| Předmět: |
|
| Zdroj: |
The Astrophysical Journal Letters, Volume 832, Number 2, L20 (2016) |
| Druh dokumentu: |
Working Paper |
| DOI: |
10.3847/2041-8205/832/2/L20 |
| Popis: |
Alfv\'enic turbulence in space is usually imbalanced: amplitudes of waves propagating parallel and anti-parallel to the mean magnetic field $B_0$ are unequal. It is commonly accepted that the turbulence is driven by (counter-)collisions between these counter-propagating wave fractions. Contrary to this, we found a new ion-scale dynamical range of the turbulence established by (co-)collisions among waves co-propagating in the same direction along $B_0$. Co-collisions become stronger than counter-collisions and produce steep non-universal spectra above certain wavenumbers dependent on the imbalance. Spectral indexes of the strong turbulence vary around -3, such that steeper spectra follow larger imbalances. Intermittency steepens the -3 spectra further, up to -3.7. Our theoretical predictions are compatible with steep variable spectra observed in the solar wind at ion kinetic scales, but further verifications are needed by correlating observed spectra with measured imbalances. |
| Databáze: |
arXiv |
| Externí odkaz: |
|
