Optimization of thrust efficiency in laser fusion rocket by using three-dimensional hybrid particle-in-cell code

An optimization study on thrust efficiency of exploding plasma in the magnetic thrust chamber for laser fusion rocket is performed by using a three-dimensional hybrid particle-in-cell code. Temporal evolution of plasma clouds expanding in a dipole magnetic field is examined. The integral-in-time picture of the exploding plasma shows a cone-like geometry. The dependences of thrust conversion efficiency eta and half-angle of the plasma expansion cone alpha on kappa (the parameter characterizes the interaction between the expanding plasma and the dipole field) are examined, and optimal values of alpha and kappa are found. The maximum thrust conversion efficiency is estimated to be about 70% from the simulation. (C) 2004 Elsevier Ltd. All rights reserved.