TY  - GEN
A1  - Woodfield, Emma E.
A1  - Horne, Richard B.
A1  - Glauert, Sarah A.
A1  - Menietti, John D.
A1  - Shprits, Yuri Y.
A1  - Kurth, William S.
T1  - Formation of electron radiation belts at Saturn by Z-mode wave acceleration
T2  - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - At Saturn electrons are trapped in the planet's magnetic field and accelerated to relativistic energies to form the radiation belts, but how this dramatic increase in electron energy occurs is still unknown. Until now the mechanism of radial diffusion has been assumed but we show here that in-situ acceleration through wave particle interactions, which initial studies dismissed as ineffectual at Saturn, is in fact a vital part of the energetic particle dynamics there. We present evidence from numerical simulations based on Cassini spacecraft data that a particular plasma wave, known as Z-mode, accelerates electrons to MeV energies inside 4 R-S (1 R-S = 60,330 km) through a Doppler shifted cyclotron resonant interaction. Our results show that the Z-mode waves observed are not oblique as previously assumed and are much better accelerators than O-mode waves, resulting in an electron energy spectrum that closely approaches observed values without any transport effects included.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1032 
KW  - astrophysical plasmas
KW  - giant planets
KW  - magnetospheric physics
KW  - diffusion
KW  - pitch angle
KW  - plasma
KW  - radio
KW  - region
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-468342
SN  - 1866-8372
IS  - 1032
ER  - 
TY  - GEN
A1  - Shprits, Yuri Y.
A1  - Menietti, J. D.
A1  - Drozdov, Alexander
A1  - Horne, Richard B.
A1  - Woodfield, Emma E.
A1  - Groene, J. B.
A1  - de Soria-Santacruz, M.
A1  - Averkamp, T. F.
A1  - Garrett, H.
A1  - Paranicas, C.
A1  - Gurnett, Don A.
T1  - Strong whistler mode waves observed in the vicinity of Jupiter's moons
T2  - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe
N2  - Understanding of wave environments is critical for the understanding of how particles are accelerated and lost in space. This study shows that in the vicinity of Europa and Ganymede, that respectively have induced and internal magnetic fields, chorus wave power is significantly increased. The observed enhancements are persistent and exceed median values of wave activity by up to 6 orders of magnitude for Ganymede. Produced waves may have a pronounced effect on the acceleration and loss of particles in the Jovian magnetosphere and other astrophysical objects. The generated waves are capable of significantly modifying the energetic particle environment, accelerating particles to very high energies, or producing depletions in phase space density. Observations of Jupiter's magnetosphere provide a unique opportunity to observe how objects with an internal magnetic field can interact with particles trapped in magnetic fields of larger scale objects.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 695 
KW  - electron acceleration
KW  - magnetic-field
KW  - diffusion
KW  - magnetosphere
KW  - Ganymede
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-426278
SN  - 1866-8372
IS  - 695
ER  -