Bremsstrahlung Emission Spectrum in Dense Z-Pinch Plasmas

Bremsstrahlung emission in dense, strongly coupled Z-pinch plasmas is investigated through first-principles molecular dynamics simulations, extending classical theory into regimes of strong coupling and strong magnetization. Using LAMMPS, two-species plasmas of positrons and ions are simulated to generate force histories from which the emission spectrum is computed. In the presence of an external magnetic field, a pronounced peak at the electron cyclotron frequency emerges in perpendicular direction due to cyclotron motion. A less significant peak also emerges in the parallel direction due to particle scattering from the perpendicular direction. A slower low-frequency decay in the perpendicular spectrum is observed and quantitatively linked to reduced diffusion coefficients in the plane orthogonal to the field. A physical model based on Coulomb interaction augmented with Lorentz force is developed aiming to extend the established model addressing the strongly coupled regime to also include a magnetic field. The model may be used to inform plasma properties that are essential for applications that create radiation sources and super intense X-ray and help tailor the spectrum.