The dielectric properties of gaseous cryogen mixtures of He, H_2, Ne, and N_2 in a temperature range of 50-80 K at pressures up to 2.0 MPa

摘要

This study investigates the dielectric properties of various mixtures of potential gaseous cryogens containing helium (He), hydrogen (H_2), neon (Ne), and nitrogen (N_2) under extended temperature and pressure ranges for high-temperature superconducting applications. We present the results of the Boltzmann analysis on a variety of binary and ternary gas mixtures in terms of the electron energy distribution function and the coefficients that represent the electron kinetic process, including the density-reduced ionization coefficient (a/AO. the density-reduced attachment coefficient (η/N), the density-reduced effective ionization coefficient ((a — η)/N), and the density-reduced critical electric field ((E/N)_(cr)). The study provides insights into the important characteristics and correlations that lead to the enhanced dielectric strength of gas mixtures and predicts further enhancements in the dielectric strengths of He-H_2 mixtures by introducing the ternary mixtures of He-H_2-N_2. The study results recommend the potential ternary gas mixtures suitable for various cryogenic operating conditions and aid in the development of superconducting applications incorporating gaseous cryogens.