title: Effect of plasma scale length on multi-MeV proton production by intense laser pulses.
abstract: The influence of the plasma density scale length on the production of MeV protons from thin foil targets irradiated at I lambda(2) = 5 x 10(19) W cm(-2) has been studied. With an unperturbed foil, protons with energy >20 MeV were formed in an exponential energy spectrum with a temperature of 2.5+/-0.3 MeV. When a plasma with a scale length of 100 microm was preformed on the back of the foil, the maximum proton energy was reduced to <5 MeV and the beam was essentially destroyed. The experimental results are consistent with an electrostatic accelerating mechanism that requires an ultrashort scale length at the back of the target.
authors: Lawrence Livermore Laboratory, Livermore, California 94550, USA.
authors: A J
authors: AJ
authors: Mackinnon
authors: M
authors: M
authors: Borghesi
authors: S
authors: S
authors: Hatchett
authors: M H
authors: MH
authors: Key
authors: P K
authors: PK
authors: Patel
authors: H
authors: H
authors: Campbell
authors: A
authors: A
authors: Schiavi
authors: R
authors: R
authors: Snavely
authors: S C
authors: SC
authors: Wilks
authors: O
authors: O
authors: Willi