Nonlocal Heat Transport in the Solar Wind

CANULLO, M.V.; COSTA, A.; FERRO FONTÁN, C.

ASTROPHYSICAL JOURNAL

IOP PUBLISHING LTD

Lugar: Londres; Año: 1996 vol. 462 p. 1005 - 1010

0004-637X

It is shown that a nonlocal, suprathermal tail originated near the solar corona base dominates the conductive energy flux at distances r ≥ 2 Rsun. A nonlocal analytical expression for the electron heat flux in weakly collisional plasmas is derived by solving the Fokker-Planck equation in a narrow, tail energy range. A correction to the anisotropy of the distribution function due to the divergent magnetic field lines was included. This term is essential to recover from the delocalization prescription, in the limit r ≥ 6Rsun, the well-known Hollweg´s Ansatz for the "collisionless" heat flux. In the intermediate region 2 Rsun ≤ r ≤ 6 Rsun, the nonlocal convolution smoothly interpolates between the classical Spitzer-Härm´s formula and the so-called collisionless régime.