Talk abstract

Dynamics of self-similarly evolving magnetic clouds
Giorgi Dalakishvili, Andria Rogava, Stefaan Poedts, Giovanni Lapenta


Magnetic clouds (MC) are "magnetized plasma clouds" moving in solar
wind. MCs transport magnetic flux and helicity from the sun. These
structures present signature of evolution in time. In our study
Magnetic clouds are considered as cylindrically symmetric magnetic
structures with low plasma beta. In order to describe the
dynamics of MCs we seek for self-similar solutions of MHD equations.
We consider longitudinal and radial
expansion of MCs, also as a particular case only radial expansion is
described. It is shown that in the self-similarly evolving, cylindrically
symmetric magnetic structure the forces are balanced.
We have derived analytical expressions for magnetic field,
plasma velocity, density and pressure. Obtained solutions are
characterised by conserved values of magnetic flux and helicity. We also used numerical code to study if system maintains self-similar structure during its evolution.