First Taste of Hot Channel in Interplanetary Space

TL;DR

This study identifies a high-temperature structure in interplanetary space linked to a hot channel eruption in the solar corona, providing insights into the magnetic and thermal properties of CMEs beyond the Sun.

Contribution

It reports the first observation of an interplanetary high-temperature structure associated with a hot channel eruption, highlighting its distinct properties from typical magnetic clouds.

Findings

The interplanetary high-temperature structure maintains elevated temperatures at 1 AU.

The structure is associated with a CME and differs from typical magnetic clouds.

A magnetic container formed by a co-rotating interaction region inhibits cooling.

Abstract

Hot channel (HC) is a high temperature ($\sim$10 MK) structure in the inner corona revealed first by Atmospheric Imaging Assembly (AIA) on board \textit{Solar Dynamics Observatory}. Eruption of HC is often associated with flare and coronal mass ejection. Previous studies suggest that HC is a good proxy of magnetic flux rope (MFR) in the inner corona, in addition to another well-known MFR candidate, the prominence-cavity structure that is with a normal coronal temperature ($\sim$1-2 MK). In this paper, we report a high temperature structure (HTS, $\sim$1.5 MK) contained in an interplanetary coronal mass ejection induced by an HC eruption. According to the observations of bidirectional electrons, high temperature and density, strong magnetic field, and its association with the shock, sheath, and plasma pile-up region, we suggest that the HTS is the interplanetary counterpart of the HC. The scale of the measured HTS is around 14 R$_\odot$, and it maintained a much higher temperature than the background solar wind even at 1 AU. It is significantly different from the typical magnetic clouds (MCs), which usually have a much lower temperature. Our study suggests that the existence of a corotating interaction region ahead of the HC formed a magnetic container to inhibit the HC expansion and cooling down to a low temperature.