Triton's atmosphere - A source of N and H for Neptune's magnetosphere

Mass loading of the Neptunian magnetosphere occurs primarily by thermal escape of H, H2, and N from Triton's upper atmosphere. The global escape rate of hydrogen is about 7 x 10 exp 25/s, determined by the global average methane photolysis rate, whereas the escape rate of nitrogen for the present preferred model is about 3.4 x 10 exp 25/s, and is controlled by the global and orbital average energy deposition rate due to precipitating magnetospheric electrons. The escape rate of H(+) and N(+) is less than 4 percent of the neutral escape rate and implies that mass loading of the Neptunian magnetosphere is not localized to Triton's corona. The ratio of hydrogen to nitrogen escape rates for the present preferred model is about 2:1, comparable to the H(+)/N(+) abundance ratio inferred for Neptune's magnetosphere.