New classification parameter of solar flares based on the maximum flux in soft X-rays and on duration of flare

TL;DR

This paper introduces a new classification parameter for solar flares, called the XI-index, based on soft X-ray flux measurements, which correlates with the total flare energy and enhances flare and CME assessment.

Contribution

The paper proposes the XI-index as a novel, physically meaningful parameter for classifying solar flares using GOES soft X-ray data, complementing existing classification systems.

Findings

XI-index correlates with total flare energy

Easily calculated from GOES data

Enhances assessment of flares and CMEs

Abstract

Solar flare activity is characterised by different classification systems, both in optical and X-ray ranges. The most generally accepted classifications of solar flares describe important parameters of flares such as the maximum of brightness of the flare in the in optical range - $H_{\alpha}$ flare class (change from F to B), area of the flare in $H_{\alpha}$ (change from S for areas less than 2 square degrees to 4 for areas more than 24.7 square degrees) and the maximum amplitude of the soft X-ray (SXR-flux) in the band 0.1 -- 0.8 nm ($F_{0.1-0.8}^{max}$) -- X-ray flares of classes from C to X. A new classification parameter of solar flares is proposed here -- the X-ray index of flare XI, based on GOES measurements of solar radiation in the SXR-range. The XI-index has a clear physical interpretation associated with the total flare energy in the SXR-range. XI is easily calculated for each flare with use of available GOES data. The XI-index can be used along with other geoeffective parameters of Solar activity to assess both flares and Coronal mass ejections (CMEs ) that are connected with them.