Attosecond pulse generation by the interaction of intense laser pulse and hydrogen-like He+ ions in Debye plasma

Abstract

Generating coherent soft X-rays and extreme ultraviolet (XUV) attosecond pulses has attracted considerable attention due to their applications as key tools in time-resolved investigations with high precision, enabling the tracing of electronic dynamics in atoms and molecules. This study focuses on the interaction between an intense multi-cycle laser pulse and hydrogen-like $H{e}^{+}$ ions within a Debye plasma. We investigate how this interaction generates high-order harmonic radiation and the production of XUV attosecond pulse trains. To achieve this, we numerically solve the time-dependent Schrödinger equation, considering twelve-cycle intense laser pulses with a wavelength of 800 nm and an intensity of $I_0=1\times 10$¹⁵ W cm⁻². The primary aim is to examine the effects of Debye screening length (specifically, the impact of plasma density and temperature) on the physical characteristics (intensity, duration, and spectrum) of the generated attosecond pulse trains. Moreover, we calculate various physical quantities, such as the time-dependent induced dipole acceleration, the time evolution of the expectation value of the Hamiltonian, and the ionization probability for the electron quivering in the laser field. These calculations provide further insight into how Debye screening length influences the high harmonic generation process. Our findings demonstrate that the physical characteristics of attosecond pulse trains can be adjusted by selecting appropriate values for plasma density and temperature, and consequently, the Debye screening length.