The precipitation of high‐energy magnetospheric electrons (E ∼ 600 eV–10 KeV) in the diffuse aurora contributes significant energy flux into the Earth's ionosphere. To fully understand the formation of this flux at the upper ionospheric boundary, ∼700–800 km, it is important to consider the coupled ionosphere‐magnetosphere system. In the diffuse aurora, precipitating electrons initially injected from the plasma sheet via wave‐particle interaction processes degrade in the atmosphere toward lower energies and produce secondary electrons via impact ionization of the neutral atmosphere. These precipitating electrons can be additionally reflected upward from the two conjugate ionospheres, leading to a series of multiple reflections through the magnetosphere. These reflections greatly influence the initially precipitating flux at the upper ionospheric boundary (700–800 km) and the resultant population of secondary electrons and electrons cascading toward lower energies. In this paper, we present the solution of the Boltzman‐Landau kinetic equation that uniformly describes the entire electron distribution function in the diffuse aurora, including the affiliated production of secondary electrons (E < 600 eV) and its energy interplay in the magnetosphere and two conjugated ionospheres. This solution takes into account, for the first time, the formation of the electron distribution function in the diffuse auroral region, beginning with the primary injection of plasma sheet electrons via both electrostatic electron cyclotron harmonic waves and whistler mode chorus waves to the loss cone, and including their subsequent multiple atmospheric reflections in the two magnetically conjugated ionospheres. It is demonstrated that magnetosphere‐ionosphere coupling is key in forming the electron distribution function in the diffuse auroral region.

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Abstract.Spatial (radial and longitudinal) malized angular distribution function, which is yield spectra for electron energy degradation in expressed as a combination of Henyey-Greenstein molecular nitrogen gas for 25-eV to 10-keV incifunction and a second Legendre polynomial [Riewe dent electrons have been generated by using a Mon-

Energy deposition by electrons having a Maxwellian energy distribution with characteristic energies 10, 30, and 100 keV, precipitating in the high-latitude upper atmosphere of Jupiter, has been studied using a continuous slowing down approximation. Electron fluxes, volume excitation, and ionization rates have been calculated. Chemical equilibrium equations have been solved for 24 ionic species using extensive hydrocarbon chemistry and incorporating diffusive transport for the ion H +. H2 Lyman and Werner bands and H Ly a intensities are obtained considering pure absorption in hydrocarbons. Comparison with Voyager ultraviolet spectrometer data requires incident energy fluxes of about 10, 18, and 45 ergs cm '2 s '1 for characteristic energies 10, 30, and 100 keY, respectively, for polar model methane abundance. Numerical experiments have been performed to study the effect of changing atomic hydrogen and methane number density, three-body reaction rates, incident energy flux, and H2(v_>4) vibrational temperature on plasma densities. Electrons with characteristic energy 30 key or somewhat higher give good overall agreement with Voyager 2 electron densities and also simulate the low-altitude peak measured by Pioneer 11. The calculated bremsstrahlung X ray flux is smaller by 1 to 2 orders of magnitude than the observed low-energy (<2 keY) X ray flux. New observations of high-energy (>2 keY) bremsstrahlung X ray emissions are required to give a definite resolution of the identity and energy of the particles responsible for the aurora on Jupiter.