Generation of counter-streaming plasmas for collisionless shock experiment

The generation mechanism of counter-streaming plasmas, by irradiating an inner-surface of the 1st-plane of double-plane target, is investigated experimentally using optical imaging and collective Thomson scattering (CTS) ion-term measurement. The CTS measurement reveals that counter-streaming plasmas exist at the same time at the same position, which is the evidence for the collisionless interaction between the counter-streaming plasmas. The generation of the 2nd-plane plasma is in two steps: First, the 2nd-plane is ablated nearly at the laser timing by radiation from the 1st-plane plasma. Then ≃ 5−7ns later, when the plasma from the 1st-plane reaches the 2ns-plane, it induces higher-density plasma generation.