Title: Radial force balance within Jupiter's dayside magnetosphere
Abstract: A local field stress technique, developed previously in a study of the Saturnian magnetosphere, is introduced to the problem of determining the radial force balance characteristics of Jupiter's magnetosphere. We begin by estimating the near‐equatorial, radial magnetic force densities using the data obtained by Voyager 1 principally on the dayside (inbound) portion of its trajectory (7.4 ≤ R ( R J ) ≤ 42). Using the low‐energy charged particle data (≳30 keV) and other published data we then explore ways in which the field forces might be balanced. Inside 22 R J the magnetic radial forces match in both magnitude and radial variation the hot particle pressure gradient forces, assuming a mix of H + and O n+ ions. Outside 22 R J we confirm qualitatively a previously reported force balance problem, and we suggest two possible solutions. The magnetic radial forces could be balanced in part either by the hot particle pressure anisotropy forces (with P ∥ / P ⊥ ∼ 1.5 for O n+ ) or by the centripetal acceleration of the cool particles that may be streaming in bulk (υ s ) parallel to the magnetic field within the small field line curvature region of the neutral sheet (with υ s ∼ υ corot ). Comparing present results with the results of our previous study, we note that contrary to common expectations, Saturn rather than Jupiter is unique in having the corotation centrifugal forces dominate over other sources of radial particle force in some regions of the middle (ring current) equatorial magnetosphere.
Publication Year: 1987
Publication Date: 1987-09-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 48
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