Comparison of electron property measurements by laser Thomson scattering and Langmuir probe in an ExB Penning discharge*

Understanding electron properties such as temperature and density in plasmas is essential for comprehending the complex physics behind plasma structure, instabilities, and transports. In this work, we measure electron properties in an E×B Penning discharge with varying magnetic field strength using laser Thomson scattering and Langmuir probes. These measurements are cross-checked to validate the results and are compared to understand the influence of magnetic field strength on the two diagnostic techniques. The obtained parameters under the experimental conditions are electron temperatures ranging from 2 eV to 5 eV and densities from 4×10¹⁰ /cm³ to 3×10¹¹ /cm³, with good agreement between the two diagnostics. Notably, the density detected by laser Thomson scattering is one of the lowest values reported with a good signal-to-noise ratio in low-temperature plasma studies. A detailed comparison of both techniques is made to evaluate the applicability and reliability in low-temperature, low-density weakly magnetized E×B plasmas.