engleski

Searching for ForbMod appropriate flux ropes

We use an analytical diffusion-expansion Forbush decrease (FD) model, ForbMod, first presented in Dumbovi¢ et al. 2018. In this diffusion-expansion model, flux rope (FR) is repre- sented by a closed magnetic structure rooted in the Sun. It has a cylindrical shape and it is initially free of cosmic ray (CR) particles. FR moves with a constant velocity and expands in a interplanetary space while the magnetic field inside it decreases. It's radius is a function of time and it expands self-similarly slowly filling with CR particles by perpendicular diffusion. From the observed FD amplitudes in the center of the FR we can calculate the values of power-law indexes for the radius and magnetic field changes. The obtained values for some events are much bigger than expected. Therefore, we examine the FR properties and show the range of values of FR parameters which would result in power-law indexes being in the expected range.

coronal mass ejections, flux rope, forbush decreases

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