Search for the low energy nuclear excitation with a femtosecond plasma: An overview and perspectives

Summary form only given. Low energy nuclear excitation in plasma has been attracting researches for almost 40 years. Despite of numerous attempts and well-established theoretical base even the feasibility of such a process has not been firmly confirmed yet. Femtosecond plasma generates bright flashes of x-rays and electrons and seems the very promising approach, but the data obtained up to now was very noisy and hardly reliable. This paper starts with an overview of the data available, including our recent results on detection of electrons due to Internal Conversion (IC) from the excited by femtosecond plasma emission ⁵⁷Fe target [1]. The excitation cross-section deduced in this experiment exceeds the theoretical values by a few orders. Hence, further experimental checks and/or theory extension and revision are needed. The second part of the paper discusses the prospects and alternative approaches to the low energy nuclear excitation. In particular, we are considering excitation due to the ionized electron motion under femtosecond laser field impact. Being in analogy to the well-known high order harmonics generation process, nuclear excitation could come from the scattering of the ionized electron upon its return to the parent nuclei. Here excitation due to inverse IC, inelastic scattering or even photoexcitation by the recombination emission might happen. Possible nuclei with isomeric levels and experimental schemes will be outlined.