Laser sources of high-energy particles and hard radiation are of great interest due to their widespread use in the creation and diagnosis of extreme states of matter. The concept of creating efficient laser sources of hard radiation based on the generation of relativistic electrons in the direct laser acceleration mode is discussed. As was confirmed in experiments [1], PW-class laser systems generating subpicosecond and femtosecond pulses of relativistic intensity are capable of creating high-current beams of ultrarelativistic electrons in an extended plasma of a near-critical density [2, 3].
            The results of experiments and modeling of the dependence of the parameters of laser-generated electron bunches and hard radiation on the parameters of laser pulses and targets are obtained and analyzed [2 - 5]. The developed approach shows ways to increase the efficiency of a wide class of secondary laser sources for various applications [6].

[1] O.N. Rosmej, N.E. Andreev, S. Zaehter, et al., New J. Phys. V. 21, P. 043044 (2019).
[2] N.E. Andreev, V.S. Popov, O.N. Rosmej, et al., Quantum Electronics, 51, 1019–1025 (2021).
[3] X. F. Shen, A. Pukhov, O. N. Rosmej, N. E. Andreev, Phys. Rev. Applied, 18, 064091 (2022).
[4] Andreev N.E., Umarov I.R., Popov V S. Bulletin of the Lebedev Physics Institute, 2023, Vol. 50, Suppl. 7, pp. S797–S805.
[5] Andreev N.E., Umarov I.R., Popov V S. Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques, 2023, Vol. 17, No. 4, pp. 848–854.
[6] M. Gunther, O.N. Rosmej, P, Tavana, et. al., Nat. Commun., V. 13, P. 170 (2022).
 

laser-matter interaction, DLA electrons, hard x-rays