MODELING OF TWISTED WARPED MAGNETOSPHERIC CONFIGURATIONS USING THE GENERAL DEFORMATION METHOD/

A new method is developed for modeling the effects of the planetary di pole tilt and of the interplanetary magnetic field (IMF) related twist ing of the cross-tail current sheet. The method extends the field defo rmation technique of Stern [1987] and makes it possible to easily repr esent a wide variety of warped magnetospheric configurations, starting from simple models with an axially symmetric magnetopause and a plana r tail current sheet. The proposed transformations do not violate the condition del.B = 0 and allow one to retain a desired distribution of the normal component of the total field at the magnetospheric boundary . Furthermore, the method makes it possible to add flexibility to the model magnetopause, so that the effects of the dipole tilt and of the IMF upon its shape can be reproduced. In particular, the transformatio n with a radially dependent rotation of the X and Z axes, while provid ing the desired tilt-related bending of the cross-tail current sheet, can also deform the magnetopause and reproduce its tilt-related asymme try, indicated by observations and reported here for the first time. T he deformation technique also allows algorithms that are more compact and faster than the currently used ones. Because of the general nature of the proposed approach it should be possible to extend it to the mo deling of other (e.g., Jovian) planetary magnetospheres.