RADIAL DIFFUSION-MODELS OF ENERGETIC ELECTRONS AND JUPITER SYNCHROTRON-RADIATION .2. TIME VARIABILITY

We used a radial diffusion code for energetic electrons in Jupiter's m agnetosphere to investigate variations in Jupiter's radio emission due to changes in the electron phase space density at L shells between 6 and 50, and due to changes in the radial diffusion parameters. We sugg est that the observed variations in Jupiter's radio emission are likel y caused by changes in the electron phase space density at some bounda ry L(1) > 6, if the primary mode of transport of energetic electrons i s radial diffusion driven by fluctuating electric and/or magnetic fiel ds induced by upper atmospheric turbulence. We noticed an excellent em pirical correlation, both in phase and relative amplitude, between cha nges in the solar wind ram pressure and Jupiter's synchrotron radiatio n if the electron phase space density at the boundary L(1) (L(1) simil ar or equal to 20-50) varies linearly with the square root of the sola r wind ram pressure, f similar to (NSVS2)(1/2) The calculations were c arried out with a diffusion coefficient D-LL=D(n)L(n) with n=3. The di ffusion coefficient which best fit the observed variations in Jupiter' s synchrotron radiation D-3=1.3+/-0.2 x 10(-9) s(-1) similar or equal to 0.041 yr(-1), which corresponds to a lagtime of approximately 2 yea rs. A comparison with previous estimates on diffusion coefficients in Jupiter's inner magnetosphere (L less than or similar to 10-20) sugges ts that all estimates can be described by n=2.5 and D-2.5=4.5 x 10(-9) s(-1) similar or equal to 0.142 year(-1). W show that the observed sh ort term (days-weeks) variations in Jupiter's radio emission cannot be explained adequately when radial diffusion is taken into account.