Naslov
Using Forbush decreases to derive the transit time of ICMEs propagating from 1 AU to Mars

Autori
Johan L. Freiherr von Forstner, Jingnan Guo, Robert F. Wimmer- Schweingruber, Donald M. Hassler, Manuela Temmer, Mateja Dumbović, Lan K. Jian, Jan K. Appel, Jaša Čalogović, Bent Ehresmann, Bernd Heber, Henning Lohf, Arik Posner, Christian T. Steigies, Bojan Vršnak, Cary J. Zeitlin

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Skup
European Space Weather Week

Mjesto i datum
Ostend, Belgija, 27.11.2017. - 01.12.2017

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
ICMEs, multi-point observations, Forbush decreases

Sažetak
The propagation of 15 interplanetary coronal mass ejections (ICMEs) from Earth's orbit (1 AU) to Mars ( $\sim$ 1.5 AU) has been studied with their propagation speed estimated from both measurements and simulations. The enhancement of magnetic fields related to ICMEs and their shock fronts cause the so-called Forbush decrease, which can be detected as a reduction of galactic cosmic rays measured on- ground. We have used galactic cosmic ray (GCR) data from in-situ measurements at Earth, from both STEREO A and B as well as GCR measurements by the Radiation Assessment Detector (RAD) instrument onboard Mars Science Laboratory (MSL) on the surface of Mars. A set of ICME events has been selected during the periods when Earth (or STEREO A or B) and Mars locations were nearly aligned on the same side of the Sun in the ecliptic plane (so-called opposition phase). Such lineups allow us to estimate the ICMEs' transit times between 1 and 1.5 AU by estimating the delay time of the corresponding Forbush decreases measured at each location. We investigate the evolution of their propagation speeds before and after passing Earth's orbit and find that the deceleration of ICMEs due to their interaction with the ambient solar wind may continue beyond 1 AU. We also find a substantial variance of the speed evolution among different events revealing the dynamic and diverse nature of eruptive solar events. Furthermore, the results are compared to simulation data obtained from two CME propagation models, namely the Drag- Based Model and ENLIL plus cone model.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

POVEZANOST RADA