Topic Report Laser-plasma simulation code: MEDUSA Student: Yi-Ping Lai Advisor: Sheng-Lung Huang Date:2012/3/8

Page  2 Outline  Introduction  Physical model  Input / output parameters  Simulation results  Improvements  Conclusions

Page  3 Introduction  The code was initially designed for inertially confined fusion studies of implosion and thermonuclear burning.  MED can calculate the one-dimensional hydrodynamic and thermodynamic behavior of a plasma irradiated by an intense laser beam.  Recently, MED is used to simulate laser-produced plasma for EUV light source (ex: UCF and UCD). Times cited:316

Page  4 Basic assumptions 1.The plasma is treated as two fluids, electrons and ions. 2.The target is a charge neutral mix of the electrons and ions. 3.The target is uniformly irradiated, reducing the problem to one-dimension.

Page  5 Physical model The plasma is described by 4 main dependent variables ρ(r,t,), u(r,t), Te(r,t), Ti(r,t), expressed at the points of a moving Lagrangian mesh.

Page  6 Mesh and integration scheme (Lagrangian coordinate) Step 1 Define the cell boundaries R j and the mass of each cells dM l (dM l can only change if a cell undergoes thermonuclear burning) Step 2 Calculate the plasma variables at cell centers Step 3 Move the cell boundaries to new positions by

Page  7 Input / output parameters Geometryplanar, cylinder, and sphere Target parametersatomic number, atomic mass, mass density, thickness Laser parametersnumber of pulses, temporal shapes, pulse durations, wavelength, intensity velocity, electron density, electron temperature, ion temperature, radiation intensity, pressure Input Output

Page  8 Simulation results 30 %Tin salt

Page  9 Improvements: higher spatial resolution The spatial resolution near the target surface greatly increases by increasing the number of grids.

Page  10 Improvements : time-dependent average charge state Time- and space-dependent charge states enable MED simulate plasma dynamics more accurate.

Page  11 Conclusions Advantages -Free open source -Short running time ( < 10 min) Disadvantages -One dimensional approximation -Cannot simulate composite targets -No plasma emissions -Low spatial resolution -Fix ion charge state

Page  12 Thanks for your listening.