CRPP/EPFL makes the headline of PRL

CRPP physicists have reported that convective cells, structures similar to those observed in boiling water in a pot, when applied at the edge of a plasma, can modify the velocity of plasma blobs that are ejected from the main confined plasma. This important result opens a new path to control these plasma packets, which could reduce their impact onto the walls of fusion devices.

The convective cells are created by an array of electrodes that can be individually biased or grounded. The plasma packets are detected by another array of probes located at about one meter from the electrodes. The first encouraging result is the observation of these convective cells propagating far away from their source. In addition, the high temporal resolution of the detection system allowed C. Theiler and his colleagues to measure the radial velocity of the packets in both conditions, i.e. with and without the presence of these convective cells and they have found a velocity difference which can reach about 3000 km/h.

The experiments were conducted in TORPEX, a basic low temperature plasma device especially designed to investigate turbulence in plasmas. This device mimics the plasma conditions that are found in fusion reactor like devices.