ELFT HÍRADÓ

[Zsolt Szep <szepzs AT cleopatra.elte.hu>]

ELTE Fizika Tanszekcsoport                                             [ELTE]
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                                ORTVAY KOLLOKVIUM

                    2001. szeptember 27., csutortok, 15 orakor
                  Az ELTE Pazmany Peter s. 1/A alatti epuleteben 
                          az 1. emeleti 1.69 eloadoban

                                   Toth Gabor
                             (ELTE Atomfizika Tsz.)
                  "Szemi-relativisztikus magnetohidrodinamika"

Kivonatos ismertetes:

Space weather describes the effects of Solar activity on Earth. One of the
challanges in the numerical modeling of space weather is that the propagation
speed, in particular the Alfven speed, can approach the speed of light in the
magnetosphere near the Earth. This poses a severe problem, since the time
steps of an explicit time integration scheme are limited by the
Courant-Friedrichs-Lewy (CFL) numerical stability condition: the waves must
not propagate more than one cell size in one time step. In a well resolved
simulation, the cell size may be as small as several 100 km-s, which limits
the time step to be less than 0.01 or even 0.001 seconds. On the other hand,
typical time scales of the magnetosphere are on the order of minutes.

I will discuss two ways of circumventing the time step limitation: (i)
replacing the classical MHD equations with the semi-relativistic MHD
equations with an artificially lowered speed of light; (ii) implicit time
integration techniques.


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terem bejarata elott teat szolgalunk fel.
Az eloadas-sorozatrol az interneten az "ortvay-koll.elte.hu" cimen talalhato
informacio.