Problem set 8, Due Fri Apr 10 April 1, 2009 A powerful laser pulse of frequency = 1014 Hz, duration 1 femtoseconds ( = 10 12 sec) and surface power W = 1020 watts per square centimeter. is impinging on hydrogen plasma of density = 10 2 g cm 3. Find a temperature to which the palsma will be heated (Temperature will be extremely high!). Hint: Is the pulse re ected from plasma or propagates inside? If re- ected, nd penetration distance, then mass within this distances, then total momentum given to plasma by pulse, then resulting velocity (it will be relativistic!); then assume that all that velocity thermalizes in a shock. A cold proton beam of density nb propagates through electron-proton plasma of density n0, nb n0, with velocity vb. Find penetration depth of the beam for (a) binary collisions only; (b) emission of Langmuir waves. 1 ...