Solids underway to warm dense matter state

This talk will be about diagnostics and modeling of the radiation-induced structural transitions in solids. Two recent experiments will be discussed in detail: (i) X-ray induced femtosecond graphitization of diamond [1], and (ii) amorphization of diamond by intense X-ray pulse [2,3]. Dedicated simulations reveal complex multistage evolution of these systems which diagnostics tools can confirm. Challenges remaining for the accurate modeling of transition of solids to warm dense matter state and the related need for improvements of the diagnostics tools are discussed. [1] F. Tavella et al., 'Soft x-ray induced femtosecond solid-to-solid phase transition', H. En. Dens. Phys 24, 22 (2017) [2] I. Inoue et al., 'Observation of femtosecond X-ray interactions with matter using an X-ray-X-ray pump-probe scheme', PNAS 113 , 1492–7 (2016) [3] N. Medvedev, B. Ziaja, 'Multistep transition of diamond to warm dense matter state revealed by femtosecond X-ray diffraction', submitted (2017)