Abstract.  In contradistinction to the main-stream fast ignition scenario based on collisional stopping in the compressed DT-fuel of relativistic electron beams (REB) in the 1-2 MeV energy range (ER) [1], we consider an ultra-relativistic extension of the Malkin-Fisch [2] attempt at using REB in the several tenths of MeV ER, and stopping them in target through strong induced Langmuir turbulence. We stress therefore the additional and substantial contribution to REB stopping of strongly inelastic reactions such as the Trident production of electron-positron pair. In the 100 MeV and higher ER bremsstrahhlung turns significant and hard Gamma come also into play to enhance these processes. We thus specifically stress electro-disintegrating deuterons and tritons. Firstly in the nucleus and eventually at higher energy with negative pion production included. In the latter case, it seems attractive to consider pion-catalyzed DT fusion in a very dense and hot plasma with no sticking. This claim is supported by preliminary estimates based on Debye like diatomic plasma orbitals. More interplays between Resulting positrons and poins of either sign are also seen to contribute to in situ stopping of ultra-relavistic REB. The latter would then drive efficiently a fast ignition target with a significantly reduced beam intensity and without hole boring issues.

References:
[1] C. Deutsch, H. Furukawa, K.Mima, M.Murakami and K. Nishimura. Phys. Rev.Letters, 77, 2483 (1996). And also K.V. Starikov and C. Deutsch, Phys. Plasmas 14 022704. (2007)
[2] V.N. Malkin and N. J. Fisch, Phys. Rev. Letter. 89, 125004 (2002)