Proton radiography investigations of plasma dynamics driven by intense lasers

The expansion of a laser-driven, high density, blast wave plasma into a lower density, ambient plasma generates collisionless shock waves (CSW) which are relevant to several astrophysical phenomena. The effects of introducing an external magnetic field or increasing the ambient plasma density on the CSW were investigated using proton radiography. The propagation of a hot electron current through a resistivity-varying material, such as foam, can result in filamentation of the current.

The degree of filamentation determines the amount of energy that is deposited into the fuel in the fast ignitor approach to inertial confinement fusion. Proton radiography imaged the electromagnetic fields of electron filaments and revealed that the resistivity instability was responsible for the onset of filamentation.T he interaction of a laser pulse with a solid target generates an azimuthal magnetic field via the Biermann battery mechanism.

The interaction of two such fields, which had parallel field lines when interacting, was investigated using proton radiography to observe magnetic field compression.