Impact of coronal mass ejections, interchange reconnection, and disconnection on heliospheric magnetic field strength

TL;DR

This paper updates the relationship between CME rate and heliospheric magnetic field strength, suggesting CMEs add flux while interchange reconnection subtracts flux, with implications for understanding magnetic field variations during solar minima.

Contribution

It refines the CME-flux relationship model and highlights discrepancies during solar minimum, proposing adjustments to existing models.

Findings

Record low magnetic field values do not contradict flux conservation.

CME rate influences heliospheric magnetic flux as predicted.

Existing models overestimate flux during solar minimum.

Abstract

An update of Owens et al. (2008) shows that the relationship between the coronal mass ejection (CME) rate and the heliospheric magnetic field strength predicts a field floor of less than 4 nT at 1 AU. This implies that the record low values measured during this solar minimum do not necessarily contradict the idea that open flux is conserved. The results are consistent with the hypothesis that CMEs add flux to the heliosphere and interchange reconnection between open flux and closed CME loops subtracts flux. An existing model embracing this hypothesis, however, overestimates flux during the current minimum, even though the CME rate has been low. The discrepancy calls for reasonable changes in model assumptions.