Monoenergetic proton backlighter for measuring E and B fields and for radiographing implosions and high-energy density plasmas „invited..

A novel monoenergetic proton backlighter source and matched imaging detector have been utilized on the OMEGA laser system to study electric E and magnetic B fields generated by laser-plasma interactions and will be utilized in the future to radiograph implosions and high-energy density HED plasmas. The backlighter consists of an imploding glass microballoon with D He fuel, producing 14.7 MeV D He protons and 3 MeV DD protons that are then passed through a mesh that divides the protons into beamlets. For quantitative study of E+B field structure, monoenergetic protons have several unique advantages compared to the broad energy spectrum used in previous experiments. Recent experiments have been performed with a single laser beam intensity of 1014 W/cm2 interacting with a CH foil, and B fields of 0.5 MG and E fields of 1.5 108 V/m have been measured using proton deflectometry. LASNEX simulations are being used to interpret these experiments. Additional information will also be presented on the application of this technique to measuring E and B fields associated with Hohlraums and directly driven implosions, to radiographically mapping the areal density R distribution in imploded capsules, and to radiographing HED plasmas. © 2006 American Institute of Physics. DOI: 10.1063/1.2228252