Constraining Ion-Scale Heating and Spectral Energy Transfer in Observations of Plasma Turbulence

T.A. Bowen (1) , A. Mallet (1) , S.D. Bale (1) , J.W. Bonnell (1) , A.W. Case (2) , B.D.G. Chandran (3) , A. Chasapis (4) , C.H.K. Chen (5) , D. Duan (1) , Thierry Dudok de Wit (6) , K. Goetz , J.S. Halekas , P.R. Harvey , J.C. Kasper (2) , Kelly E Korreck , D. Larson (1) , R. Livi (1) , R.J Macdowall (7) , D.M. Malaspina , M.D. Mcmanus (1) , M. Pulupa (1) , M. Stevens , P. Whittlesey (1)

1 SSL - Space Sciences Laboratory [Berkeley]
2 Smithsonian Astrophysical Observatory
3 UNH - University of New Hampshire
4 LASP - Laboratory for Atmospheric and Space Physics [Boulder]
5 QMUL - Queen Mary University of London
6 LPC2E - Laboratoire de Physique et Chimie de l'Environnement et de l'Espace
7 GSFC Solar System Exploration Division

We perform a statistical study of the turbulent power spectrum at inertial and kinetic scales observed during the first perihelion encounter of the Parker Solar Probe. We find that often there is an extremely steep scaling range of the power spectrum just above the ion-kinetic scales, similar to prior observations at 1 A.U., with a power-law index of around −4. Based on our measurements, we demonstrate that either a significant (>50%) fraction of the total turbulent energy flux is dissipated in this range of scales, or the characteristic nonlinear interaction time of the turbulence decreases dramatically from the expectation based solely on the dispersive nature of nonlinearly interacting kinetic Alfvén waves.

Domains: Sciences of the Universe [physics]

T.A. Bowen, A. Mallet, S.D. Bale, J.W. Bonnell, A.W. Case, et al.. Constraining Ion-Scale Heating and Spectral Energy Transfer in Observations of Plasma Turbulence. Physical Review Letters, 2020, 125 (2), 8 p. ⟨10.1103/PhysRevLett.125.025102⟩. ⟨insu-02923463⟩