
TY  - JOUR
A1  - Wheatland, MS 
A1  - Melrose, DB 
T1  - Cross-field Current Closure Below the Solar Photosphere
JF  - Australian Journal of Physics
JO  - Aust. J.  Phys.
Y1  - 1994
VL  - 47
IS  - 3
SP  - 361
EP  - 374
KW  - 
UR  - https://doi.org/10.1071/PH940361 
N2  - A simple model is developed to describe how an externally imposed current closes as a function of time below the photosphere. A vertical current density is assumed to turn on at the photospheric boundary. The model implies that the subsequent closure of the current in the sub-photosphere depends only on the ratio RA/ R, where RA = /-LaVA is the Alfvenic impedance of the photosphere and = I/o-pI is the resistance corresponding to the conductivity O-p and a characteristic length 1. For RA/R » 1, current closure occurs at a front, propagating with the Alfven speed. For RA/ R 1, current closure is a diffusive process ahead and behind a slowly propagating Alfvenic front. The first case is the relevant one for the Sun, where RA/ R /VA, for VA in kilometres per second. 
ER  -

