outer boundary

Li, Z., Hudson, M., & Chen, Y. (2014). Radial diffusion comparing a THEMIS statistical model with geosynchronous measurements as input. Journal Of Geophysical Research: Space Physics, 119, 1863-1873. http://doi.org/10.1002/jgra.v119.310.1002/2013JA019320 (Original work published March 2014)