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Title: Self-consistent model of the interstellar pickup protons, Alfvenic turbulence, and core solar wind in the outer heliosphere

Abstract

In this study, a self-consistent model of the interstellar pickup protons, the slab component of the Alfvénic turbulence, and core solar wind (SW) protons is presented for r ≥ 1 along with the initial results of and comparison with the Voyager 2 (V2) observations. Two kinetic equations are used for the pickup proton distribution and Alfvénic power spectral density, and a third equation governs SW temperature including source due to the Alfvén wave energy dissipation. A fraction of the pickup proton free energy, fD , which is actually released in the waveform during isotropization, is taken from the quasi-linear consideration without preexisting turbulence, whereas we use observations to specify the strength of the large-scale driving, C sh, for turbulence. The main conclusions of our study can be summarized as follows. (1) For C sh ≈ 1-1.5 and f D ≈ 0.7-1, the model slab component agrees well with the V2 observations of the total transverse magnetic fluctuations starting from ~8 AU. This indicates that the slab component at low-latitudes makes up a majority of the transverse magnetic fluctuations beyond 8-10 AU. (2) The model core SW temperature agrees well with the V2 observations for r ≳ 20 AU if fmore » D ≈ 0.7-1. (3) A combined effect of the Wentzel-Kramers-Brillouin attenuation, large-scale driving, and pickup proton generated waves results in the energy sink in the region r ≲ 10 AU, while wave energy is pumped in the turbulence beyond 10 AU. Without energy pumping, the nonlinear energy cascade is suppressed for r ≲ 10 AU, supplying only a small energy fraction into the k-region of dissipation by the core SW protons. A similar situation takes place for the two-dimensional turbulence. (4) The energy source due to the resonant Alfvén wave damping by the core SW protons is small at heliocentric distances r ≲ 10 AU for both the slab and the two-dimensional turbulent components. As a result, adiabatic cooling mostly controls the model SW temperature in this region, and the model temperature disagrees with the V2 observations in the region r ≲ 20 AU.« less

Authors:
 [1];  [1];  [2];  [2];  [1]
  1. Florida Institute of Technology, Melbourne, FL (United States)
  2. Univ. of Alabama, Huntsville, AL (United States)
Publication Date:
Research Org.:
Univ. of Alabama, Huntsville, AL (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1325984
Grant/Contract Number:  
SC0008334
Resource Type:
Accepted Manuscript
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 757; Journal Issue: 1; Journal ID: ISSN 0004-637X
Publisher:
Institute of Physics (IOP)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; interplanetary medium; solar wind; Sun: heliosphere; turbulence; waves

Citation Formats

Gamayunov, Konstantin V., Zhang, Ming, Pogorelov, Nikolai V., Heerikhuisen, Jacob, and Rassoul, Hamid K. Self-consistent model of the interstellar pickup protons, Alfvenic turbulence, and core solar wind in the outer heliosphere. United States: N. p., 2012. Web. doi:10.1088/0004-637X/757/1/74.
Gamayunov, Konstantin V., Zhang, Ming, Pogorelov, Nikolai V., Heerikhuisen, Jacob, & Rassoul, Hamid K. Self-consistent model of the interstellar pickup protons, Alfvenic turbulence, and core solar wind in the outer heliosphere. United States. doi:10.1088/0004-637X/757/1/74.
Gamayunov, Konstantin V., Zhang, Ming, Pogorelov, Nikolai V., Heerikhuisen, Jacob, and Rassoul, Hamid K. Wed . "Self-consistent model of the interstellar pickup protons, Alfvenic turbulence, and core solar wind in the outer heliosphere". United States. doi:10.1088/0004-637X/757/1/74. https://www.osti.gov/servlets/purl/1325984.
@article{osti_1325984,
title = {Self-consistent model of the interstellar pickup protons, Alfvenic turbulence, and core solar wind in the outer heliosphere},
author = {Gamayunov, Konstantin V. and Zhang, Ming and Pogorelov, Nikolai V. and Heerikhuisen, Jacob and Rassoul, Hamid K.},
abstractNote = {In this study, a self-consistent model of the interstellar pickup protons, the slab component of the Alfvénic turbulence, and core solar wind (SW) protons is presented for r ≥ 1 along with the initial results of and comparison with the Voyager 2 (V2) observations. Two kinetic equations are used for the pickup proton distribution and Alfvénic power spectral density, and a third equation governs SW temperature including source due to the Alfvén wave energy dissipation. A fraction of the pickup proton free energy, fD , which is actually released in the waveform during isotropization, is taken from the quasi-linear consideration without preexisting turbulence, whereas we use observations to specify the strength of the large-scale driving, C sh, for turbulence. The main conclusions of our study can be summarized as follows. (1) For Csh ≈ 1-1.5 and fD ≈ 0.7-1, the model slab component agrees well with the V2 observations of the total transverse magnetic fluctuations starting from ~8 AU. This indicates that the slab component at low-latitudes makes up a majority of the transverse magnetic fluctuations beyond 8-10 AU. (2) The model core SW temperature agrees well with the V2 observations for r ≳ 20 AU if fD ≈ 0.7-1. (3) A combined effect of the Wentzel-Kramers-Brillouin attenuation, large-scale driving, and pickup proton generated waves results in the energy sink in the region r ≲ 10 AU, while wave energy is pumped in the turbulence beyond 10 AU. Without energy pumping, the nonlinear energy cascade is suppressed for r ≲ 10 AU, supplying only a small energy fraction into the k-region of dissipation by the core SW protons. A similar situation takes place for the two-dimensional turbulence. (4) The energy source due to the resonant Alfvén wave damping by the core SW protons is small at heliocentric distances r ≲ 10 AU for both the slab and the two-dimensional turbulent components. As a result, adiabatic cooling mostly controls the model SW temperature in this region, and the model temperature disagrees with the V2 observations in the region r ≲ 20 AU.},
doi = {10.1088/0004-637X/757/1/74},
journal = {Astrophysical Journal},
number = 1,
volume = 757,
place = {United States},
year = {2012},
month = {9}
}

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