Can the Solar Wind be Driven by Magnetic Reconnection in the Sun's Magnetic Carpet?

TL;DR

This study uses Monte Carlo simulations of the Sun's magnetic carpet to evaluate whether magnetic reconnection can drive the solar wind, concluding it is unlikely for both slow and fast wind streams.

Contribution

The paper introduces a novel Monte Carlo modeling approach of the magnetic carpet to assess reconnection-driven solar wind acceleration, challenging previous hypotheses.

Findings

Reconnection energy fluxes are insufficient for wind acceleration in quiet regions.

Imbalanced coronal holes may have enough energy flux, but recycling times are too long.

Magnetic reconnection in the magnetic carpet is unlikely to drive the solar wind.

Abstract

The physical processes that heat the solar corona and accelerate the solar wind remain unknown after many years of study. Some have suggested that the wind is driven by waves and turbulence in open magnetic flux tubes, and others have suggested that plasma is injected into the open tubes by magnetic reconnection with closed loops. In order to test the latter idea, we developed Monte Carlo simulations of the photospheric "magnetic carpet" and extrapolated the time-varying coronal field. These models were constructed for a range of different magnetic flux imbalance ratios. Completely balanced models represent quiet regions on the Sun and source regions of slow solar wind streams. Highly imbalanced models represent coronal holes and source regions of fast wind streams. The models agree with observed emergence rates, surface flux densities, and number distributions of magnetic elements. Despite having no imposed supergranular motions, a realistic network of magnetic "funnels" appeared spontaneously. We computed the rate at which closed field lines open up (i.e., recycling times for open flux), and we estimated the energy flux released in reconnection events involving the opening up of closed flux tubes. For quiet regions and mixed-polarity coronal holes, these energy fluxes were found to be much lower than required to accelerate the solar wind. For the most imbalanced coronal holes, the energy fluxes may be large enough to power the solar wind, but the recycling times are far longer than the time it takes the solar wind to accelerate into the low corona. Thus, it is unlikely that either the slow or fast solar wind is driven by reconnection and loop-opening processes in the magnetic carpet.