AbstractThe characteristics of plasma waves propagating in the Earth's plasmasphere and magnetosphere are important in terms of understanding the plasma environment in which these waves are excited and propagate. The propagation direction is a critical in propagation analysis of ELF/VLF band waves. The Means, eigenvector, amplitude, and SVD methods have been proposed previously to estimate the direction of arrival of a single wave, and the wave distribution function (WDF) method, which solves the ill‐posed problem, has been proposed to estimate the propagation direction of multiple arriving waves. In this paper, we propose a stochastically extended WDF method. Conventional WDF methods are based on maximum posterior probability estimation; however, the proposed method uses a Markov chain Monte Carlo method. In the proposed method, the estimated solution is obtained based on the sampling approximation by obtaining multiple samples following the posterior distribution. In addition, the WDF is discretized and quantized to improve calculation stability and efficiency. From the sampled WDF, the mean value of the WDF and 95% credible interval can be calculated without arbitrary parameters. The proposed method is more objective than conventional methods and can be used effectively as a basis for performance evaluation of the WDF method.