Some peculiarities of solar plasma flows from coronal holes
Abstract
Using a method of calculating magnetic fields in the corona in the potential approximation and by comparing results of these calculations with analysis results on observational data, it is shown that: (a) for sufficiently stable coronal holes (CH), mean angular size Δαdependences of superradial onedimensional ̂tf(Δα) ⋍ sol15/√Δα( degree) and twodimensional ƒ _{a}(S) = [ ̂tf _{a}] ^{2} ( S being the CH area) divergence magnetic tubes originating from coronal holes, are about the same for all types of CH: equatorial, offequatorial and polar; (b) deviations from curves ̂tf _{a}(Δα) and ƒ _{a}(S) result from the fact that the magnetic flux of the tube can, to a greater or lesser extent, be limited by the (surrounding it) neutral line (NL) loop or magnetic fluxes from neighbouring CH; (c) the relationship V_{m}( S) ( V_{m} being the averaged velocity in the central part of the flow at the Earth's orbit emanating from a CH of area S) for offequatorial and equatorial CH represents an approximately linear growth of V_{m} vs S when S < S _{c} ⋍ 5.10 ^{10}km^{2} and V _{m} ⋍ const when S > S_{c}; and (d) plasma flows from polar CH, whose boundary runs at latitudes above 60°70°, do not reach the Earth's latitude.
 Publication:

Planetary and Space Science
 Pub Date:
 April 1990
 DOI:
 10.1016/00320633(90)90139H
 Bibcode:
 1990P&SS...38..459E
 Keywords:

 Coronal Holes;
 Mathematical Models;
 Solar Wind;
 Approximation;
 Divergence;
 Laplace Equation;
 Magnetic Flux;
 Magnetohydrodynamic Flow;
 Solar Magnetic Field;
 Solar Physics