This thesis looks at the effects that electron-ion Coulomb collisions have onudfast electron transport in solid density plasma. The study of the fast electrons generated in ultra-high intensity laser-plasma interactions is important due to theirudenvisioned use in the fast ignition approach to inertial confinement fusion.udCollisions have been added to the particle-in-cell (PIC) code EPOCH in orderudto study the propagation of fast electron beams in various solid density targets. Byudusing a collisional PIC model several of the assumptions used in previous studies are not required. The code solves the full Maxwell equations (including theuddisplacement current), does not require assumptions of Ohm’s law and of Spitzerudresistivity and does not require the background distributions to be Maxwellian.udThe thesis begins with summaries of the background theory and of the previous work performed in this area. The PIC method is then discussed and the way inudwhich collisions were added to EPOCH is outlined. The results from several collisional PIC simulations with different target Z values are then discussed and com-udpared to both collisionless PIC simulation results and hybrid simulation results.udThe effects of collisions have then been examined by looking into numerous aspects of the simulations that have been performed. Firstly, the generation of fieldsudwithin the plasma and the subsequent filamentation of the fast electron beam areudexamined. The effects that the collisions have on the electron distributions withinudthe plasma are then investigated with particular attention given to the divergenceudof the fast electrons, the energy and momentum distributions of the electrons andudthe background temperatures within the plasma. Finally, the results of the simulations are used to assess the accuracy of the Spitzer resistivity approximation thatudis used in hybrid codes.
展开▼
