  Filamentation of linear polarized ultrashort laser pulses in non-axisymmetric
optical schemes with preferential directions to the optical axis in dependence
on the beam orientation was experimentally studied. Our experiments
demonstrated strong influence of a laser beam orientation on self-focusing of
the beam and plasma generation during filamentation. Maximum of linear plasma
density generated by an astigmatic laser pulse was different in both meridional
and sagittal foci and depended on the beam orientation. A difference of linear
plasma density was observed in the case of superposition of two parts of the
laser beam going through a two-hole diaphragm depending on the beam orientation
and through a slit for collinear and normal slit orientation relative to the
beam orientation. Laser pulses in IR and UV wavelength domains led to similar
result.
