On the polarization and the convection current models

A recent letter by Chawla and Unz (ibid., Vol. 54, pp. 1103-1105, Aug. 1966) has suggested that the problems in electromagnetic theory can be solved by two different models:´ a) polarization current mode (PCM), b) convection current mode (CCM). In the letter, they remarked equivalence between these two models and, by CCM, they obtained the formal solution to the electric field in a moving anisotropic plasma. The purpose of this letter is to point out that, although both PCM and CCM give the same answer as far as the dispersion relation is concerned as stated by Tai (1965), Poynting vectors obtained by PCM and CCM are entirely different from each other. Thus, it is noted that the problems of radiation in moving media should be carefully formulated.