  We have carried out a 3D ideal-MHD (Magnetohydrodynamic) simulation to study
the evolution of laser generated plasma plume in a moderate external magnetic
field (0.13 T) oriented perpendicular to the flow direction of the plasma
plume. The simulation shows that the plasma plume pushes the external magnetic
field lines outward in the direction of the expansion. This leads to
compression and bending of the magnetic field lines.The force resulting from
the change in shape and the density of magnetic field lines opposes the
expansion of the plume. An elliptic layer of shocked plasma is formed at the
plasma/external field interface leaving a cavity in the plume core due to the
outward expansion and the inertia of the plume. As the plasma pressure drops
due to expansion, the imbalance between the magnetic energy and the internal
energy results in the collapse of the cavity. These observations have striking
similarities with the observations of the experiments [Phys. Plasmas 24, 033511
(2017)] performed recently to study the plasma plume expansion in the presence
of an external transverse magnetic field. This similarity indicates that the
physical mechanisms dominantly governing the plasma plume expansion in the
moderate magnetic field are aptly described in the ideal MHD regime. The
studies thus show that the laser generated plasma plume can be utilized to
carry out interesting experiments on MHD phenomena in a simple laboratory set
up.
