Hot-Wire Measurements of the Heat Transfer in a Partially Magnetized Potassium Plasma

A hot-wire device designed as a gas-loaded heat pipe has been used to study the axial magnetic field influence on the heat transfer in a potassium vapor plasma at low vapor pressures pK = 400 to 1200 Pa, temperatures Tw of the tungsten filament in the range 2000 to 2800 K, and magnetic field iIntensity B = 0.182 to 0.364 T. As a result of the applied magnetic field B, the measured thermal flux Q decreases. The separation between the heat fluxes transferred by radiation Q,, by atoms Qa, and by electrons Qc can be accomplished analyzing the decrement AQ. A procedure to analyze the measured data in the presence and in the absence of the magnetic field in order to define the different mechanisms of the heat transfer has been introduced. The electron thermal conductivity can be obtained in the Frost approximation by means of the well-known transport phenomena theory using available electron-potassium atom cross sections in the range of electron energies E= 0.06 to 2 eV.