  We study the strongly magnetized white dwarf configurations in a
self-consistent manner as a progenitor of the over-luminous type-Ia supernovae.
We compute static equilibria of white dwarf stars containing a strong magnetic
field and present the modification of white dwarf mass-radius relation caused
by the magnetic field. From a static equilibrium study, we find that a maximum
white dwarf mass of about 1.9 M$_\odot$ may be supported if the interior
poloidal field is as strong as approximately $10^{10}$ T. On the other hand if
the field is purely toroidal the maximum mass can be more than 5 M$_\odot$. All
these modifications are mainly from the presence of Lorenz force. The effects
of i) modification of equation of state due to Landau quantization, ii)
electrostatic interaction due to ions, iii) general relativistic calculation on
the stellar structure and, iv) field geometry are also considered. These
strongly magnetised configurations are sensitive to magnetic instabilities
where the perturbations grow at the corresponding Alfven time scales.
