The regulation of the dual external field on the Joule-Thomson effect of Fermi gas

In light of the Thomas-Fermi semi-classical approximation, the regulation of the dual external potential field of the uniform electric field and harmonic oscillator field on the chemical potential and the Joule-Thomson effect of Fermi gas was studied and the overt functional relationship between the chemical potential and the internal energy of the charged Fermi particle systems of the uniform electric field and harmonic oscillator field with the temperature changes in the limited temperature range was given and the regulation of the dual external potential field on the chemical potential and the Joule-Thomson effect of Fermi gas was further analyzed. The research findings show that with the rise of temperature, the value of the Joule-Thomson coefficient of the charged Fermi particle systems presents a gradual change from negative to positive and the critical temperature T_C declines with the increase of external electric field and that the existence of the external potential may bring about a positive Joule-Thomson effect at an appropriate temperature. (authors)