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Title: Spatial confinement of the IBEX Ribbon: A dominant turbulence mechanism

The narrow ribbon of enhanced energetic neutral atom flux observed by the Interstellar Boundary Explorer spacecraft has prompted numerous ideas to explain its structure and properties. One of these ideas is the 'neutral solar wind' scenario, which identifies the source particles as pickup protons in the local interstellar medium originating in solar wind charge-exchange interactions. This scenario has been thought to require unrealistically weak pitch-angle scattering of the pickup protons to explain the narrow structure. Recently, Schwadron and McComas suggested that this structure could result from a spatial retention of the pickup protons, rather than from a restricted pitch-angle distribution. Here, we present a physically motivated, quantitative mechanism to produce such a spatial configuration. This mechanism is based on the 'dominant turbulence' assumption, which can be applied where the production of new pickup protons is slow, and has been used to successfully explain the level of turbulent heating observed in the outer solar wind. This formalism predicts a pickup isotropization process which adds or subtracts energy from the ambient turbulent fluctuations, depending on the initial pitch angle of the pickup protons. We show that a simple model of this process can yield a ribbon structure in qualitative agreement with themore » observations. The results of this simple model are not yet quantitatively satisfactory, but we suggest several improvements which may reduce the quantitative discrepancy.« less
Authors:
 [1]
  1. Institute for the Study of Earth, Oceans and Space, University of New Hampshire, Durham, NH 03824 (United States)
Publication Date:
OSTI Identifier:
22356807
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 787; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ATOMS; CHARGE-EXCHANGE INTERACTIONS; DISTRIBUTION; FLUCTUATIONS; INCLINATION; MAGNETIC FIELDS; PLASMA; PROTONS; RETENTION; SCATTERING; SOLAR WIND; TURBULENCE; TURBULENT HEATING