# The behaviour of galactic cosmic ray intensity during solar activity cycle 24

## TL;DR

This study analyzes long-term variations of galactic cosmic ray intensity during solar cycle 24, revealing cycle-specific patterns, time-lags, and the applicability of linear models, contributing to understanding cosmic ray behavior in relation to solar activity.

## Contribution

It applies and validates methodologies from previous cycles to cycle 24, showing that linear models better describe GCR behavior during even-numbered cycles, with a detailed analysis of time-lags.

## Key findings

- Cycle 24 had a 2-4 month lag in GCR response.
- Linear models fit cycle 24 data better than elliptical models.
- Cycle 24's behavior aligns with previous even-numbered cycles.

## Abstract

We have studied long-term variations of galactic cosmic ray (GCR) intensity in relation to the sunspot number (SSN) during the most recent solar cycles. This study analyses the time-lag between the GCR intensity and SSN, and hysteresis plots of the GCR count rate against SSN for solar activity cycles 20-23 to validate a methodology against previous results in the literature, before applying the method to provide a timely update on the behaviour of cycle 24. Cross-plots of SSN vs GCR show a clear difference between the odd-numbered and even-numbered cycles. Linear and elliptical models have been fit to the data with the linear fit and elliptical model proving the more suitable model for even-numbered and odd-numbered solar activity cycles respectively, in agreement with previous literature. Through the application of these methods for the 24th solar activity cycle, it has been shown that cycle 24 experienced a lag of 2-4 months and follows the trend of the preceding activity cycles albeit with a slightly longer lag than previous even-numbered cycles. It has been shown through the hysteresis analysis that the linear fit is a better representative model for cycle 24, as the ellipse model doesn't show a significant improvement, which is also in agreement with previous even-numbered cycles.