Plasma Diagnostics I

In this work, we explore the coherent excitation of plasma waves in low-temperature plasma by crossed ultrashort laser pulses and the retrieval of plasma parameters using a sounding or probe pulse scattered from the decaying grating. These dynamics are explored through a weakly coupled modeling framework consisting of a 1D1V simulation of plasma grating excitation on a frozen ion background and time-dependent scattering calculations in the slowly varying envelope approximation. Calculations are performed over a range of key dimensionless parameters including ω_pτ_p ε [0.1, 10] and α ε [0.1, 10]. In particular, this work explores the impact of several key physical mechanisms on the signal pulse amplitude and spectrum, including 1) collisional damping modeled by the BGK operator, and 2) multi-photon ionization. Based on the findings, we discuss the potential LTP applications of the proposed laser diagnostic, and the finding's impact on the development of an experimental laser diagnostic.