Strong-field physics at relativistic intensity

The dynamics of multiply charged ions is discussed in the presence of extremely intense laser pulses. Various schemes are put forward how such ions could be employed for medical applications [1] and to characterize extremely intense laser pulses. Furthermore various laser-based scenarious are presented regarding vacuum nonlinearities [2] as well as muon [3] and electron pair creation [4]. \newline [1] Y. I. Salamin, Z. Harman, C H Keitel, Phys. Rev. Lett. 100, 155004 (2008) \newline [2] A. Di Piazza, K. Z. Hatsagortsyan, C. H. Keitel, Phys. Rev. Lett. 100, 010403 (2008) \newline [3] C. M\"{u}ller, C. Deneke, C. H. Keitel, Phys. Rev. Lett. 101, 060402 (2008) \newline [4] E. L\"{o}tstedt, U. D. Jentschura, C. H. Keitel, Phys. Rev. Lett. 101, 203001 (2008).