24 synoptic maps of 296 prominence average magnetic fields measured by Hanle effect during cycle XXI ascending phase. (arXiv:2007.08219v1 [astro-ph.SR])

24 synoptic maps of 296 prominence average magnetic fields measured by Hanle effect during cycle XXI ascending phase. (arXiv:2007.08219v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Bommier_V/0/1/0/all/0/1">V. Bommier</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Leroy_J/0/1/0/all/0/1">J.L. Leroy</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sahal_Brechot_S/0/1/0/all/0/1">S. Sahal-Brechot</a>

Aims : The aim of the present paper is to publish 24 synoptic maps of solar
filaments, in which 296 prominence average unambiguous magnetic field vectors
were determined by Pic-du-Midi observations between 1974 and 1982, which is the
ascending phase of cycle XXI. Methods : The magnetic field was determined by
interpretation of the Hanle effect observed in the He I D3 line. Previous
results about the prominence field polarity and prominence chirality were
applied to solve the fundamental ambiguity. The measurements were averaged in
each prominence for accuracy reasons. Results : The result is twofold. First,
alternating field directions can be observed from one neutral line to the next
one. Second, a general field alignment is found along a solar North-South field
distorted under the differential rotation effect.

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