Possible effects of solar wind transient modulation of Galactic Cosmic Rays on high latitude atmosphere

GUTIERREZ, CHRISTIAN; DASSO, SERGIO

Workshop; GRAPE/RESOURCE Online Workshop -; 2020

The effects of energetic galactic cosmic rays (GCR) can be very strong on the polar cap regions,affecting the physical and chemical properties, as well as the electrical characteristics of the ionosphere andatmosphere. In particular, GCRs arriving at high geomagnetic latitudes (above 65°–70°) are importantcomponents for particles ionization during nights. In particular, the role of GCRs is significant for formationof the lower part (50-80 km) of the ionospheric D-region, they have strong influence on the ionization,chemical and electrical state in the region 5-100 km. At altitudes below 30 km, the primary cosmic raysinitiate a nucleonic-electromagnetic cascade in the atmosphere, with the main energy losses, resulting inionization, dissociation and excitation of molecules.In this work, we study the response of GCR fluxes due to the presence of solar wind transients. Inparticular we analyze consequences of the presence of Interplanetary Coronal Mass Ejections ICMEs onGCRs fluxes arriving Antarctica, for the period of 1998-2017, using the Richardson and Cane ICMECatalogue. We analyze solar wind data from MAG and SWEPAM instruments aboard the ACE spacecraftwith a time cadence of 16 and 64 seconds respectively, and GCRs data from MacMurdo neutron monitorwith a time cadence of 1 hour. We study different characteristics of ICMEs and their impacts on thevariability of the flux of GCRs.The results presented in this work will help to understand one of the aspects of the Sun-Earthcoupling, involving the effects of transient solar wind events on the variability of flux of cosmic rays on highlatitudes. It will also try to explain how ICMEs with strong B and high bulk velocity influence on the rate ofionization that take place in the atmosphere, which affect strongly the atmospheric conductivity.