Isochoric heating in heterogeneous solid targets with ultrashort laser pulses

We study ultrafast heating of thin plastic foils by intense laser irradiation theoretically using collisional two-dimensional particle-in-cell simulations. We find that the laser-generated hot electrons are confined laterally by self-generated resistive magnetic fields, heating the laser focal area beyond keV electron temperatures isochorically in a few picoseconds. Using this confinement one can excite shock waves that compress the plasma beyond solid density and achieve keV thermal plasmas before the plasma disassembles. Such shocks can be launched at material interfaces inside the target where jumps in the average ionization state and thus electron density lead to gigabar pressure. They propagate stably over picoseconds accompanied by multi-megagauss magnetic fields, and thus have a potential for various applications in high energy density physics. (c) 2007 American Institute of Physics.