On expansion of magnetic clouds in the solar wind
06 Aug 2009
1Astronomical Institute, Academy of Sciences of the Czech Republic, 14131 Praha 4, Czech Republic
2Physics Department, University of Athens, Panepistimioupoli-Kouponia, Athens 15771, Greece
3Prairie View A& M University, Mail Stop 2250, PO Box 519, Prairie View TX 77446, USA
4Institute of Terrestrial Magnetism, Ionosphere, and Radio Wave Propagation of Russian Academy of Sciences, Troitsk, 142190, Russia
Abstract. Magnetic clouds are supposed to be large interplanetary flux ropes propagating away from the Sun. Due to enhanced inner magnetic pressure, they expand during their travel. We have analyzed 21 magnetic clouds from Wind observations and fitted them by our model. Comparison of the time-dependent model with observations is shown for several cases with a detailed discussion. The model describes behavior of compared quantities satisfactorily. In addition to magnetic field vectors, also velocity vectors were modeled and it was found that radial velocity component behaves as expected. Analysis of velocity components put models under a more strict test and yields more confidence into models and derived magnetic cloud parameters.