Letter to the Editor

Sensitivity of solar wind mass flux to coronal temperature^★

¹ Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Surrey RH5 6NT, UK
e-mail: d.stansby@ucl.ac.uk
² LESIA, Observatoire de Paris, PSL Research University, CNRS, UPMC University Paris 6, University Paris-Diderot, Meudon, France
³ Physics and Astronomy Department, University of Florence, Sesto Fiorentino, Italy
⁴ Department of Physics, Imperial College London, London, SW7 2AZ, UK
⁵ Physics Department, University of California, Berkeley, CA 94720-7300, USA
⁶ Space Sciences Laboratory, University of California, Berkeley, CA 94720-7450, USA

Received: 29 October 2020
Accepted: 7 December 2020

Abstract

Solar wind models predict that the mass flux carried away from the Sun in the solar wind should be extremely sensitive to the temperature in the corona, where the solar wind is accelerated. We perform a direct test of this prediction in coronal holes and active regions using a combination of in situ and remote sensing observations. For coronal holes, a 50% increase in temperature from 0.8 to 1.2 MK is associated with a tripling of the coronal mass flux. This trend is maintained within active regions at temperatures over 2 MK, with a four-fold increase in temperature corresponding to a 200-fold increase in coronal mass flux.