Coronal Heating Driven by A Magnetic-gradient Pumping Mechanism in Solar Plasmas

TL;DR

This paper proposes a magnetic gradient pumping mechanism where magnetic field gradients drive energetic particles upward, heating the solar corona to over a million degrees and explaining hot plasma upflows like spicules.

Contribution

It introduces a novel magnetic gradient pumping mechanism that explains coronal heating and hot plasma upflows in the Sun.

Findings

Coronal temperature can reach above 1 million degrees.

Upflow velocities are estimated at 40 km/s in chromosphere and 130 km/s in corona.

Magnetic flux tubes act as pumps for energetic particles.

Abstract

The solar coronal heating is a longstanding mystery in astrophysics. Considering that the solar magnetic field is spatially inhomogeneous with considerable magnetic gradient from solar surface to the corona, this work proposes a magnetic gradient pumping (MGP) mechanism and try to explain the formation of hot plasma upflows, such as the hot type II spicules and hot plasma ejections, etc. In MGP mechanism, the magnetic gradients drive the energetic particles to move upwards from the underlying solar atmosphere and form hot upflows. These upflow energetic particles deposit in corona and make it becoming very hot. Roughly estimations indicate that the solar corona can be heated to above 1 million degrees, and the upflow velocity is about 40 km/s in chromosphere and about 130 km/s in the corona. The solar magnetic flux tubes act as pumpers to extract energetic particles from the underlying thermal photosphere, convey them and deposit in the corona. The deposition of energetic particles will make the corona become hot, and their escaping from the photosphere will make the underlying photosphere a bit cold. This mechanism present a natural explanation to the mystery of solar coronal heating.