Observation of a critical pressure gradient for the stabilization of interchange modes in simple magnetized toroidal plasmas

L. Federspiel, B. Labit, P. Ricci, A. Fasoli, I. Furno, C. Theiler
2009 Physics of Plasmas  
The existence of a critical pressure gradient needed to drive the interchange instability is experimentally demonstrated in the simple magnetized torus TORoidal Plasma EXperiment ͓A. Fasoli et al., Phys. Plasmas 13, 055902 ͑2006͔͒. This gradient is reached during a scan in the neutral gas pressure p n . Around a critical value for p n , depending on the magnetic configuration and on the injected rf power, a small increase in the neutral gas pressure triggers a transition in the plasma behavior.
more » ... he plasma behavior. The pressure profile is locally flattened, stabilizing the interchange mode observed at lower neutral gas densities. The measured value for the critical gradient is close to the linear theory estimate.
doi:10.1063/1.3204704 fatcat:n5jhpuhisfedto2whtpsa6x23y