posted by Don .
Could you please help me: Does plasma have a definite shape or volume?
No. It behaves like a gas; however magnetic and electric fields can transfer momentum and energy to it.
It is possible to "contain" plasma in a "magnetic bottle" (curved magentic field lines; not surfaces) for brief periods, but only temporarily.
Matter (including plasma) can be trapped in specially shaped laser beams also, but only in very small quantities.