We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Wave‐Particle Interaction of Alfvén Waves in Jupiter's Magnetosphere: Auroral and Magnetospheric Particle Acceleration.
- Authors
Saur, Joachim; Janser, Sascha; Schreiner, Anne; Clark, George; Mauk, Barry H.; Kollmann, Peter; Ebert, Robert W.; Allegrini, Frederic; Szalay, Jamey R.; Kotsiaros, Stavros
- Abstract
We investigate spatial and temporal scales at which wave‐particle interaction of Alfvén waves occurs in Jupiter's magnetosphere. We consider electrons, protons, and oxygen ions and study the regions along magnetic flux tubes where the plasma is the densest, that is, the equatorial plasma sheet, and where the plasma is the most dilute, that is, above the ionosphere, where auroral particle acceleration is expected to occur. We find that within a dipole L‐shell of roughly 30, the electron inertial length scale in the auroral region is the dominating scale, suggesting that electron Landau damping of kinetic Alfvén waves can play an important role in converting field energy into auroral particle acceleration. This mechanism is consistent with the broadband bidirectional electron distributions frequently observed by Juno. Due to interchange‐driven mass transport in Jupiter's magnetosphere, its magnetosphere‐ionosphere coupling is expected to be mostly not in local force balance. This might be a key reason for the dominant role of Alfvénically driven stochastic acceleration compared to the less frequently occurring, locally forced‐balanced, and thus static mono‐energetic unidirectional acceleration. Outside of approximately L = 30, the ion gyroperiod is the dominating scale suggesting that ion cyclotron damping of heavy ions plays a major role in heating magnetospheric plasma. We also present properties of the dispersion relationship and the polarization relationships of kinetic Alfvén waves including the important effects from the relativistic correction due to the displacement current in Ampère's law. Key Points: Kinetic Alfvén waves in Jupiter's magnetosphere generate broadband bidirectional auroral electron beamsIn Jupiter's middle and outer magnetosphere, ion cyclotron damping causes ion heating in plasma sheetStochastic acceleration due to Alfvén waves can have its root cause in magnetosphere‐ionosphere coupling locally not in stress balance
- Subjects
WAVE-particle interactions; PLASMA Alfven waves; MAGNETOSPHERE of Jupiter; MAGNETIC flux; PLANETARY ionospheres
- Publication
Journal of Geophysical Research. Space Physics, 2018, Vol 123, Issue 11, p9560
- ISSN
2169-9380
- Publication type
Article
- DOI
10.1029/2018JA025948