The new findings for dynamic process of inward diffusion in the magnetospheric plasma are reported on the Ring Trap 1 (RT-1) experiment: (i) the evolution of local density profile in the self-organized process has been analyzed by the newly developed tomographic reconstruction applying a deep learning method; (ii) the impact of neutral-gas injection excites low-frequency fluctuations, which continues until the peaked density profile recovers. The fluctuations have magnetic components (suggesting the high-beta effect) which have two different frequencies and propagation directions. The phase velocities are of the order of magnetization drifts, and both the velocities and the intensities increase in proportion to the electron density. The self-regulating mechanism of density profile works most apparently in the naturally made confinement system, magnetosphere, which teaches the basic physics of long-lived structures underlying every stationary confinement scheme.