Search Publications
Location and size of the global source region of whistler mode chorus
Santolík, O.; Parrot, M.; Hayosh, M.
We use multicomponent measurements of the four Cluster spacecraft and a backward ray tracing simulation to estimate the location and size of the global source of whistler mode chorus emissions in the magnetic equatorial plane. For the first time, analysis is made in a broad range of latitudes in both hemispheres along a single Cluster orbit. Our r…
What can be learned from the absence of auroral X-ray emission from Saturn?
Cravens, Thomas E.; Hui, Yawei; Schultz, David R. +1 more
To understand the origin and magnitude of the present upper limit observations of Saturn's auroral X-ray emission, we use simple models based on the mechanism that leads to analogous emission at Jupiter, charge transfer between ion precipitation and atmospheric gas. Several putative sources and characteristics of the precipitation are considered, …
Simultaneous FAST and Double Star TC1 observations of broadband electrons during a storm time substorm
Dandouras, I.; Fazakerley, A. N.; Le Contel, O. +13 more
Broadband electrons (BBEs) exhibit remarkable electron flux enhancements over a broad energy range (0.03-30 keV) near the equatorward edge of the auroral oval during geomagnetic storms. Here, we report a BBE event observed by the Fast Auroral Snapshot (FAST) satellite at 1355-1359 UT, ∼61°-66° invariant latitudes, ∼0600 magnetic local time (MLT), …
Characteristics of storm time electric fields in the inner magnetosphere derived from Cluster data
Farrugia, C. J.; Khotyaintsev, Yu. V.; Torbert, R. B. +6 more
Storm-time electric fields in the inner magnetosphere measured by Cluster are reported in this study. First, we show two events around the time when Dst index is at a minimum. The electric field possibly related to subauroral ion drifts and/or undershielding is measured inside the inner edge of the electron plasma sheet in the eveningside. For the…
Role of oxygen ions in the formation of a bifurcated current sheet in the magnetotail
Veltri, P.; Zimbardo, G.; Greco, A. +1 more
Cluster observations in the near-Earth magnetotail have shown that sometimes the current sheet is bifurcated, i.e., it is divided in two layers. The influence of magnetic turbulence on ion motion in this region is investigated by numerical simulation, taking into account the presence of both protons and oxygen ions. The magnetotail current sheet i…
Possible wave modes of wideband nonthermal continuum radiation in its source region
Santolík, O.; Grimald, S.
Nonthermal continuum (NTC) electromagnetic radiation is generated within the Earth's magnetosphere and radiated to the outer space. We present cases of a specific type of NTC, which appears as multiple wide bands on the spectrograms recorded by the Cluster spacecraft just outside the plasmapause. This NTC comes from several sources located in the …
Longitude dependences of energetic H+ and O+ at Saturn
Krimigis, S. M.; Mitchell, D. G.; Carbary, J. F. +2 more
The charge-energy-mass spectrometer instrument in the Cassini spacecraft measured differential fluxes of protons (2.8-236 keV) and oxygen ions (8.8-236 keV) from July 2004 to August 2007. The fluxes were bin-averaged in Saturn longitude system (SLS) longitude within ±5 RS of the equator and between 8 and 12 RS in radial dista…
Comparisons between ion distributions retrieved from ENA images of the ring current and contemporaneous, multipoint ion measurements recorded in situ during the major magnetic storm of 15 May 2005
Barabash, S.; Liu, Z. X.; Brandt, P. C. +5 more
The Neutral Atom Detector Unit (NUADU) aboard the TC-2 spacecraft recorded energetic neutral atom (ENA) image data for >3 h during part of the main and recovery phases of a major magnetic storm on 15 May 2005. A custom designed, constrained linear inversion method was applied to retrieve ring current ion distributions in the ENA records out to …
Plasma conditions and the structure of the Jovian ring
Horányi, Mihály; Juhász, Antal
We explore the dynamics of small charged dust particles in Jupiter's innermost magnetosphere and show that the systematic charge variation of the grains results in surprisingly short lifetimes. Assuming a constant production of small dust particles via continual micrometeoroid bombardment of the larger parent bodies of the main ring, this model re…
A new approach for deriving the solar irradiance from nonflaring solar upper atmosphere plasmas at 2 × 104 ≤ T ≤ 2 × 107 K
Fontes, C. J.; Landi, E.; Doschek, G. A. +7 more
We propose a new approach for deriving the solar irradiance due to the emission by solar upper atmosphere plasmas at 2 × 104 ≤ T ≤ 2 × 107 K for wavelengths shorter than 800 Å. Our approach is based on a new understanding of the properties of the solar upper atmosphere; specifically, the discovery that the majority of emissio…