Nonlocal transient transport and thermal barriers in Rijnhuizen Tokamak project plasmas

In the Rijnhuizen Tokamak Project plasmas, a transient rise of the core ele ctron temperature is observed when hydrogen pellets are injected tangential ly to induce fast cooling of the peripheral region. High-resolution Thomson scattering measurements show that the T-e rise is associated with large te mperature gradients in the region 1 < q < 2. This region acts as a layer of transiently increased thermal resistivity (transport barrier) when probed by fast heat pulses from modulated electron cyclotron heating.