PSP Bibliography


  • Clicking on the DOI link will open a new window with the original bibliographic entry from the publisher.
  • Clicking on a single author will show all publications by the selected author.
  • Clicking on a single keyword, will show all publications by the selected keyword.

Magnetic Helicity Reversal in the Corona at Small Plasma Beta

AuthorBourdin, Philippe; Singh, Nishant; Brandenburg, Axel;
KeywordsAstrophysics - Solar and Stellar Astrophysics; dynamo; magnetohydrodynamics: MHD; methods: numerical; parker solar probe; Physics - Plasma Physics; Solar Probe Plus; Solar wind; Sun: corona; Sun: magnetic fields

Solar and stellar dynamos shed small-scale and large-scale magnetic helicity of opposite signs. However, solar wind observations and simulations have shown that some distance above the dynamo both the small-scale and large-scale magnetic helicities have reversed signs. With realistic simulations of the solar corona above an active region now being available, we have access to the magnetic field and current density along coronal loops. We show that a sign reversal in the horizontal averages of the magnetic helicity occurs when the local maximum of the plasma beta drops below unity and the field becomes nearly fully force free. Hence, this reversal is expected to occur well within the solar corona and would not directly be accessible to in situ measurements with the Parker Solar Probe or SolarOrbiter. We also show that the reversal is associated with subtle changes in the relative dominance of structures with positive and negative magnetic helicity.

Year of Publication2018
JournalThe Astrophysical Journal
Number of Pages2
Date Published12/2018