A New Method to Determine the Temperature of CMEs Using a Coronagraph Filter System

TL;DR

This paper presents a novel method to determine the temperature of coronal mass ejections (CMEs) by analyzing the intensity ratio at two specific wavelengths using a coronagraph system, enhancing CME thermal diagnostics.

Contribution

The paper introduces a new technique utilizing a two-filter coronagraph system to measure CME temperature based on spectral line broadening effects.

Findings

Validated the method with the GCS model for 3D CME density

Demonstrated temperature inference from intensity ratios

Discussed the significance of the method for CME analysis

Abstract

The coronagraph is an instrument enables the investigation of faint features in the vicinity of the Sun, particularly coronal mass ejections (CMEs). So far coronagraphic observations have been mainly used to determine the geometric and kinematic parameters of CMEs. Here, we introduce a new method for the determination of CME temperature using a two filter (4025 A and 3934 A) coronagraph system. The thermal motion of free electrons in CMEs broadens the absorption lines in the optical spectra that are produced by the Thomson scattering of visible light originating in the photosphere, which affects the intensity ratio at two different wavelengths. Thus the CME temperature can be inferred from the intensity ratio measured by the two filter coronagraph system. We demonstrate the method by invoking the graduated cylindrical shell (GCS) model for the 3 dimensional CME density distribution and discuss its significance.