**2.2 Ground level enhancements**

GLE events have more concerns with space radiation due to a harder spectrum and large energy intensity. Mewaldt et al. [18] estimated an average power-law index of about 3.18 at energies of >40 MeV and energy intensity of >50 MeV for GLE events in solar cycle 23. He also found out that these events exhibited larger ratios of Fe*=*O ratios and 3He-rich element composition. **Table 1** shows the detailed properties of the two proton events associated with GLE that occurred during the solar cycle 24. The properties of the GLE events were obtained from Gopalswamy et al. [19]—GLE 71 and

**Figure 1.**

*A bar graph showing the yearly averaged sunspot number and yearly number of SPEs from 2010 to 2017.*

**Figure 2.**

*The variation of sunspot number (a), proton flux at three energy levels (b), integrated X-ray flux (c), and cosmic ray intensity recorded at Oulu neutron monitor station (d) over solar cycle 24.*

Cohen and Mewaldt [20] and Gopalswamy et al. [21]—GLE 72. It's observed that the GLE events are associated with high CME shock speeds, powerful X-ray flares and originated from the western hemisphere. This provides a better magnetic connection between the sun's active region and the observer along the sun-earth line [1, 22, 23].
