Active Longitude and Solar Flare Occurrences

TL;DR

This study analyzes the spatial and temporal patterns of solar flares in relation to active longitudes, revealing that most flares occur near these regions and exhibit significant periodic fluctuations, which could improve flare forecasting.

Contribution

The paper introduces a new method to identify active longitudes and demonstrates their correlation with flare occurrence and temporal fluctuations, enhancing solar flare prediction capabilities.

Findings

Over 60% of flares occur within ±36° of active longitudes.

Flare activity shows significant fluctuations at 0.8, 1.3, and 1.8-year periods.

Most flares are concentrated near the active longitudinal belt.

Abstract

The aim of the present work is to specify the spatio-temporal characteristics of flare activity observed by the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) and Geostationary Operational Environmental Satellite (GOES) satellites in connection with the behaviour of the longitudinal domain of enhanced sunspot activity known as active longitude (AL). By using our method developed for this purpose, we identified the AL in every Carrington Rotation provided by the Debrecen Photoheliographic Data (DPD). The spatial probability of flare occurrence has been estimated depending on the longitudinal distance from AL in the northern and southern hemispheres separately. We have found that more than the 60\% of the RHESSI and GOES flares is located within $\pm 36^{\circ}$ from the active longitude. Hence, the most flare-productive active regions tend to be located in or close to the active longitudinal belt. This observed feature may allow predicting the geo-effective position of the domain of enhanced flaring probability. Furthermore, we studied the temporal properties of flare occurrence near the active longitude and several significant fluctuations were found. More precisely, the results of the method are the following fluctuations: $0.8$ years, $1.3$ years and $1.8$ years. These temporal and spatial properties of the solar flare occurrence within the active longitudinal belts could provide us enhanced solar flare forecasting opportunity.