Scaling the energy conversion rate from magnetic field reconnection to different bodies

TL;DR

This paper investigates how magnetic field reconnection energy conversion rates scale across different celestial bodies, revealing a cubic dependence on magnetic field strength and explaining diverse astrophysical phenomena.

Contribution

It introduces a theoretical and experimental scaling law for energy conversion rates in magnetic reconnection across various astrophysical environments.

Findings

Energy conversion rate scales as magnetic field strength cubed divided by density square root.

Explains variability in solar flares, Mercury's magnetic flux, and absence on Jupiter and Saturn.

Predicts electric fields at Solar Probe Plus perihelion could reach tens of volts/meter.

Abstract

Magnetic field reconnection is often invoked to explain electromagnetic energy conversion in planetary magnetospheres, stellar coronae, and other astrophysical objects. Because of the huge dynamic range of magnetic fields in these bodies, it is important to understand energy conversion as a function of magnetic field strength and related parameters. It is conjectured theoretically and shown experimentally that the energy conversion rate per unit area in reconnection scales as the cube of an appropriately weighted magnetic field strength divided by the square root of an appropriately weighted density. With this functional dependence, the energy release in flares on the Sun, the large and rapid variation of the magnetic flux in the tail of Mercury, and the apparent absence of reconnection on Jupiter and Saturn, may be understood. Electric fields at the perihelion of the Solar Probe Plus mission may be tens of volts/meter.