The PBX-M tokamak has an array of unique features that allow it to stu
dy regimes of enhanced confinement and stability. In particular, becau
se of its divertor operation, PBX-M has proved to be a valuable contri
butor to identifying and understanding various features of H-mode phys
ics. To be reported here are recent results of H-mode studies of m=1 b
ias induced H-modes, L- to H-transitions, including suppression of tur
bulent transport, ELMs and other related energy loss mechanisms, and I
on Bernstein Wave modification of H-mode discharges.