Naslov
Heliospheric propagation of coronal mass ejections: comparison of numerical WSA-ENLIL+cone model and analytical drag-based model

Autori
Vršnak, Bojan ; Temmer, Manuela ; Žic, Tomislav ; Taktakishvili, Alexandre ; Dumbović, Mateja ; Mostl, Christian ; Veronig, Astrid ; Mays, Leila ; Odstrčil, Dušan

Izvornik
The Astrophysical journal. Supplement series (0067-0049) 213 (2014), 2; 21-1

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
magnetohydrodynamics (MHD) – methods: analytical – methods: numerical – methods: statistical – solar–terrestrial relations – solar wind – Sun: coronal mass ejections (CMEs)

Sažetak
Real-time forecasting of the arrival of coronal mass ejections (CMEs) at Earth, based on remote solar observations, is one of the central issues of space-weather research. In this paper, we compare arrival-time predictions calculated applying the numerical “WSA-ENLIL+Cone model” and the analytical “drag-based model” (DBM). Both models use coronagraphic observations of CMEs as input data, thus providing an early space-weather forecast two to four days before the arrival of the disturbance at the Earth, depending on the CME speed. It is shown that both methods give very similar results if the drag parameter Γ = 0.1 is used in DBM in combination with a background solar-wind speed of w = 400 km s−1. For this combination, the mean value of the difference between arrival times calculated by ENLIL and DBM is Δ = 0.09±9.0 hr with an average of the absolute-value differences of |Δ| = 7.1 hr. Comparing the observed arrivals (O) with the calculated ones (C) for ENLIL gives O − C = −0.3 ± 16.9 hr and, analogously, O − C = +1.1 ± 19.1 hr for DBM. Applying Γ = 0.2 with w = 450 km s−1 in DBM, one finds O − C = −1.7 ± 18.3 hr, with an average of the absolute-value differences of 14.8 hr, which is similar to that for ENLIL, 14.1 hr. Finally, we demonstrate that the prediction accuracy significantly degrades with increasing solar activity.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

POVEZANOST RADA