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Title: STABILITY OF A PICKUP ION RING-BEAM POPULATION IN THE OUTER HELIOSHEATH: IMPLICATIONS FOR THE IBEX RIBBON

Abstract

First results from NASA's Interplanetary Boundary Explorer mission showed an unexpected 'ribbon' of enhanced energetic neutral atom (ENA) flux spanning most of the sky. One explanation put forward suggests that the ribbon may be produced by secondary ENAs originating from pickup ions (PUIs) in the outer heliosheath (OHS). These PUIs are generated when primary ENAs born in the solar wind and inner heliosheath cross the heliopause and charge exchange in the nearby interstellar medium. One of the core assumptions underpinning this theory is that the newly born PUI ring is relatively stable with respect to wave generation, so that it can undergo charge exchange before becoming isotropized. We test this assumption using a linear kinetic theory and hybrid simulations of a low-density PUI ring interacting with instability-generated waves in a warm plasma of the OHS. It is shown that a broadband spectrum of waves is excited as a result of the cyclotron instability that efficiently scatters the ring ions. We also show that the ambient fluctuations in the OHS are unlikely to produce a measurable degree of resonant scattering of PUIs because their intensity is too low compared with the waves excited by the instability.

Authors:
; ;  [1]; ;  [2]
  1. Department of Physics, University of Alabama, Huntsville, AL 35899 (United States)
  2. Center for Space Plasma and Aeronomic Research, University of Alabama, Huntsville, AL 35899 (United States)
Publication Date:
OSTI Identifier:
21457110
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 719; Journal Issue: 2; Other Information: DOI: 10.1088/0004-637X/719/2/1097; Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTROPHYSICS; CHARGE EXCHANGE; CYCLOTRON INSTABILITY; ION RINGS; NASA; RESONANCE SCATTERING; SIMULATION; SOLAR WIND; TURBULENCE; INELASTIC SCATTERING; INSTABILITY; NATIONAL ORGANIZATIONS; PHYSICS; PLASMA INSTABILITY; PLASMA MICROINSTABILITIES; SCATTERING; SOLAR ACTIVITY; STELLAR ACTIVITY; STELLAR WINDS; US ORGANIZATIONS

Citation Formats

Florinski, V, Zank, G P, Heerikhuisen, J, Hu, Q, and Khazanov, I. STABILITY OF A PICKUP ION RING-BEAM POPULATION IN THE OUTER HELIOSHEATH: IMPLICATIONS FOR THE IBEX RIBBON. United States: N. p., 2010. Web. doi:10.1088/0004-637X/719/2/1097.
Florinski, V, Zank, G P, Heerikhuisen, J, Hu, Q, & Khazanov, I. STABILITY OF A PICKUP ION RING-BEAM POPULATION IN THE OUTER HELIOSHEATH: IMPLICATIONS FOR THE IBEX RIBBON. United States. https://doi.org/10.1088/0004-637X/719/2/1097
Florinski, V, Zank, G P, Heerikhuisen, J, Hu, Q, and Khazanov, I. 2010. "STABILITY OF A PICKUP ION RING-BEAM POPULATION IN THE OUTER HELIOSHEATH: IMPLICATIONS FOR THE IBEX RIBBON". United States. https://doi.org/10.1088/0004-637X/719/2/1097.
@article{osti_21457110,
title = {STABILITY OF A PICKUP ION RING-BEAM POPULATION IN THE OUTER HELIOSHEATH: IMPLICATIONS FOR THE IBEX RIBBON},
author = {Florinski, V and Zank, G P and Heerikhuisen, J and Hu, Q and Khazanov, I},
abstractNote = {First results from NASA's Interplanetary Boundary Explorer mission showed an unexpected 'ribbon' of enhanced energetic neutral atom (ENA) flux spanning most of the sky. One explanation put forward suggests that the ribbon may be produced by secondary ENAs originating from pickup ions (PUIs) in the outer heliosheath (OHS). These PUIs are generated when primary ENAs born in the solar wind and inner heliosheath cross the heliopause and charge exchange in the nearby interstellar medium. One of the core assumptions underpinning this theory is that the newly born PUI ring is relatively stable with respect to wave generation, so that it can undergo charge exchange before becoming isotropized. We test this assumption using a linear kinetic theory and hybrid simulations of a low-density PUI ring interacting with instability-generated waves in a warm plasma of the OHS. It is shown that a broadband spectrum of waves is excited as a result of the cyclotron instability that efficiently scatters the ring ions. We also show that the ambient fluctuations in the OHS are unlikely to produce a measurable degree of resonant scattering of PUIs because their intensity is too low compared with the waves excited by the instability.},
doi = {10.1088/0004-637X/719/2/1097},
url = {https://www.osti.gov/biblio/21457110}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 719,
place = {United States},
year = {Fri Aug 20 00:00:00 EDT 2010},
month = {Fri Aug 20 00:00:00 EDT 2010}
}