Judgment of paradigms for magnetic reconnection in coronal loops

TL;DR

This paper challenges the traditional view of magnetic reconnection in coronal loops by emphasizing the role of magnetic field line chaos, proposing a new paradigm where reconnection occurs faster and with lower current densities than previously thought.

Contribution

It introduces a new paradigm for magnetic reconnection that accounts for magnetic chaos, reducing the required current density and timescale compared to traditional models.

Findings

Magnetic chaos enables faster reconnection.

Current density scales with ln(R_m) instead of R_m.

Simulations support the chaos-based paradigm.

Abstract

The traditional paradigm for magnetic field lines changing connections ignores magnetic field line chaos and requires an extremely large current density, $j_{max}\propto R_m$, flowing in thin sheets of thickness $1/R_m$, where $R_m$ is the magnetic Reynolds number. The time required for a general natural evolution to take a smooth magnetic field into such a state is rarely considered. Natural evolutions generally cause magnetic field lines to become chaotic. A fast change in field line connections then arises on the timescale defined by the evolution multiplied by a $\ln(R_m)$ factor, and the required maximum current density scales as $\ln(R_m)$. Even when simulations support the new paradigm based on chaos, they have been interpreted as supporting the old. How this could happen is an important example for plasma physics of Kuhn's statements about the acceptance of paradigm change and on Popper's views on the judgment of truth in science.