Open AccessEnergetic particle evidence for magnetic filaments in Jupiter's magnetotail
Author(s) -
Hill Matthew E.,
Haggerty Dennis K.,
McNutt Ralph L.,
Paranicas Christopher P.
Publication year - 2009
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2009ja014374
Subject(s) - physics , jovian , pluto , jupiter (rocket family) , solar wind , ion , plasma sheet , dispersion (optics) , planet , astrophysics , computational physics , plasma , astronomy , magnetosphere , geophysics , spacecraft , saturn , nuclear physics , optics , quantum mechanics
Jupiter's immense magnetotail was uniquely traversed and observed in situ to 2562 Jovian radii (R J = 71,492 km) for the first time by the Pluto‐bound New Horizons spacecraft during the first half of 2007. We show evidence that energetic ions with sulfur‐rich composition traceable to Io's volcanism originated 150 ± 40 R J antisunward of the planet and were recurrently released and funneled by the magnetic field down the magnetotail. Ions detected at New Horizons by the Pluto Energetic Particle Spectrometer Science Investigation (PEPSSI) instrument showed unmistakable signatures of velocity dispersion. We performed a survey of the unambiguous dispersion events observed by PEPSSI and provide a quantitative description of each event's dispersion characteristics. Energetic ions are sensitive probes of the magnetic field structure in the magnetotail; so, for a case study of one of the most interesting events, beginning on day of year 118, 28 April 2007, we are also able to estimate small‐scale features of the magnetotail. Our observations (which include energies above ∼2 keV/nuc and total energies below ∼1 MeV), combined with straightforward simulations of particle flow, are consistent with narrow spatial structures, or filaments, on the order of 5 R J wide in the ∼400 R J wide > 9000 R J long magnetotail; the Solar Wind Around Pluto plasma instrument measurements show coherent structures on a much larger scale (∼500 R J ) in the same region.