Transverse and Longitudinal Thermomagnetic Waves in Conducting Media

The excited thermomagnetic wave in anisotropic conducting media is analyzed theoretically at different directionsof the gradient of the temperature TÑ , relative to the wave vector k . It is shown that at k T^ Ñ (transverse wave) and at || k T ÑT|| Tk (longitudinal wave) the oscillation frequency has different values. In thesetwo cases, the excited thermomagnetic waves are increasing. The increment of the increase in each case hasdifferent values. It is shown that the values in different directions of electrical conductivity for the excitationand for the increase of thermomagnetic waves play a major role. Depending on the selected conditions, thefrequency of thermomagnetic waves changes significantly. In both cases (i.e. k T ^ÑTk and || k T ÑT|| Tk ), thechoice of coordinate systems does not affect the theoretical calculation at all. The frequency and increment ofthermomagnetic waves do not depend on the choice of coordinate systems. However, the choice of coordinatesystems significantly affects the choice of the direction of the magnetic field and the temperature gradient.The velocity of hydrodynamic motions of charge carriers turns towards the temperature gradient. The excitedmagnetic field upon excitation of charge carriers (electrons) depends very much on the direction of the temperaturegradient. The oscillation frequency of excitation of thermomagnetic waves depends linearly on thevalue of the temperature gradient. The increment of growth of excited thermomagnetic waves has differentvalues for different values of the tensor of electrical conductivity of the medium ik s . It is stated that if thewave vector of excited waves and the constant gradient of the temperature are directed at an angle, i.e.(kkÑT = kkÑT ccossa, éëékÑT ùûù = kÑÑT ssina) theoretical calculation of the oscillation frequency and the incrementof growth fails due to the high degree of the dispersion equation relative to the oscillation frequency. Thistheory does not consider the electric field created by the redistribution of charge carriers. The theory takes intoaccount that the constant temperature 0T , external field 0E , and the mean free path of charge carriers satisfythe relation 0 0 0 k T eE l , 0 k is a constant. At 0 0 0 k T eE l and 0 0 0 k T > eE l a very high temperature is required,i.e. melting of the medium begins.