Search Publications
Kinetic Alfvén turbulence below and above ion cyclotron frequency
Wu, D. J.; Zhao, J. S.; Voitenko, Y. M. +1 more
Alfvénic turbulent cascade perpendicular and parallel to the background magnetic field is studied accounting for anisotropic dispersive effects and turbulent intermittency. The perpendicular dispersion and intermittency make the perpendicular-wave-number magnetic spectra steeper and speed up production of high ion cyclotron frequencies by the turb…
Generation of magnetosonic waves over a continuous spectrum
Lu, Quanming; Gao, Xinliang; Zhima, Zeren +3 more
Magnetosonic waves, also known as equatorial noise emission, were found to have discrete frequency structures, which is consistent with instability caused by proton ring distribution. Nonetheless, nondiscrete structure, i.e., a broadband spectrum over a continuous frequency range, has been reported. We investigate the question whether proton ring …
Magnetic reconnection in Saturn's magnetotail: A comprehensive magnetic field survey
Thomsen, M. F.; Jackman, C. M.; Smith, A. W.
Reconnection within planetary magnetotails is responsible for locally energizing particles and changing the magnetic topology. Its role in terms of global magnetospheric dynamics can involve changing the mass and flux content of the magnetosphere. We have identified reconnection related events in spacecraft magnetometer data recorded during Cassin…
Propagation of small size magnetic holes in the magnetospheric plasma sheet
Zhang, H.; Hamrin, M.; Rème, H. +19 more
Magnetic holes (MHs), characteristic structures where the magnetic field magnitude decreases significantly, have been frequently observed in space plasmas. Particularly, small size magnetic holes (SSMHs) which the scale is less than or close to the proton gyroradius are recently detected in the magnetospheric plasma sheet. In this study of Cluster…
Jupiter's X-ray and EUV auroras monitored by Chandra, XMM-Newton, and Hisaki satellite
Hasegawa, H.; Fujimoto, M.; Masters, A. +17 more
Jupiter's X-ray auroral emission in the polar cap region results from particles which have undergone strong field-aligned acceleration into the ionosphere. The origin of precipitating ions and electrons and the time variability in the X-ray emission are essential to uncover the driving mechanism for the high-energy acceleration. The magnetospheric…
Interaction of ULF waves with different ion species: Pitch angle and phase space density implications
Zong, Q. G.; Rankin, R.; Wang, Y. F. +2 more
ULF waves can accelerate/decelerate the charged particles including the ring current ions via drift-bounce resonance, which play an important role in the dynamics of ring current during storm times. This study compares the different behaviors of oxygen ions (10.5-35.1 keV) and protons (0.3-12.3 keV) which simultaneously interact with Pc5 ULF waves…
Rotational modulation of Saturn's radio emissions after equinox
Gurnett, D. A.; Kurth, W. S.; Ye, S. -Y. +2 more
Saturn kilometric radiation (SKR), narrowband emission, and auroral hiss are periodically modulated due to Saturn's rotation, and the periods were found to vary with time. We analyze Cassini observations of Saturn's radio emissions with the main focus on the four years 2012-2015. It is shown that the rotation rates of SKR north and south were diff…
Variation of Jupiter's aurora observed by Hisaki/EXCEED: 2. Estimations of auroral parameters and magnetospheric dynamics
Tsuchiya, Fuminori; André, Nicolas; Fujimoto, Masaki +7 more
Jupiter's auroral parameters are estimated from observations by a spectrometer EXCEED (Extreme Ultraviolet Spectroscope for Exospheric Dynamics) on board Japanese Aerospace Exploration Agency's Earth-orbiting planetary space telescope Hisaki. EXCEED provides continuous auroral spectra covering the wavelength range over 80-148 nm from the whole nor…
Mirror modes in the Earth's magnetosheath: Results from a global hybrid-Vlasov simulation
Vainio, Rami; Pfau-Kempf, Yann; Ganse, Urs +5 more
We investigate mirror mode structures in the Earth's magnetosheath using our global kinetic Vlasiator simulation, which models ion behavior through their distribution function and treats electrons as a charge-neutralizing fluid. We follow the evolution of waves as they advect along velocity streamlines through the magnetosheath. We find that mirro…
Reconstructing the magnetosphere from data using radial basis functions
Tsyganenko, Nikolai A.; Andreeva, Varvara A.
A new method is proposed to derive from data magnetospheric magnetic field configurations without any a priori assumptions on the geometry of electric currents. The approach utilizes large sets of archived satellite data and uses an advanced technique to represent the field as a sum of toroidal and poloidal parts, whose generating potentials Ψ