chemical heating, cosmic rays, and molecular gas (trac #234)

[cloudy-bot]

reported by: @CloudyLex

we should look into this

Title:  
    Cosmic-ray and X-ray Heating of Interstellar Clouds and Protoplanetary Disks
Authors:    
    Glassgold, Alfred E.; Galli, Daniele; Padovani, Marco
Publication:    
    eprint arXiv:1208.0523
Publication Date:   
    08/2012
Origin: 
    ARXIV
Keywords:   
    Astrophysics - Galaxy Astrophysics
Comment:    
    39 pages, accepted for publication in the Astrophysical Journal
Bibliographic Code: 
    2012arXiv1208.0523G
Abstract
Cosmic-ray and X-ray heating are derived from the electron energy 
loss calculations of Dalgarno, Yan and Liu for hydrogen-helium gas 
mixtures. These authors treated the heating from elastic scattering 
and collisional de-excitation of rotationally excited hydrogen 
molecules. Here we consider the heating that can arise from all 
ionization and excitation processes, with particular emphasis on 
the reactions of cosmic-ray and X-ray generated ions with the heavy 
neutral species, which we refer to as chemical heating. In 
molecular regions, chemical heating dominates and can account for
 50 per cent of the energy expended in the creation of an ion pair.
 The heating per ion pair ranges in the limit of negligible 
electron fraction from about 4.3 eV for diffuse atomic gas, to 
about 13 eV for the moderately dense regions of molecular clouds 
and to about 18 eV for the very dense regions of protoplanetary 
disks. An important general conclusion of this study is that 
cosmic-ray and X-ray heating depends on the physical properties of 
the medium, i.e., on the molecular and electron fractions, the 
total density of hydrogen nuclei, and to a lesser extent on the 
temperature. It is also noted that chemical heating, the dominant 
process for cosmic-ray and X-ray heating, plays a role in UV 
irradiated molecular gas. 

Migrated from https://www.nublado.org/ticket/234

{
    "status": "new",
    "changetime": "2019-02-04T13:07:06Z",
    "_ts": "1549285626580696",
    "description": "we should look into this\n{{{\nTitle:\t\n\tCosmic-ray and X-ray Heating of Interstellar Clouds and Protoplanetary Disks\nAuthors:\t\n\tGlassgold, Alfred E.; Galli, Daniele; Padovani, Marco\nPublication:\t\n\teprint arXiv:1208.0523\nPublication Date:\t\n\t08/2012\nOrigin:\t\n\tARXIV\nKeywords:\t\n\tAstrophysics - Galaxy Astrophysics\nComment:\t\n\t39 pages, accepted for publication in the Astrophysical Journal\nBibliographic Code:\t\n\t2012arXiv1208.0523G\nAbstract\nCosmic-ray and X-ray heating are derived from the electron energy \nloss calculations of Dalgarno, Yan and Liu for hydrogen-helium gas \nmixtures. These authors treated the heating from elastic scattering \nand collisional de-excitation of rotationally excited hydrogen \nmolecules. Here we consider the heating that can arise from all \nionization and excitation processes, with particular emphasis on \nthe reactions of cosmic-ray and X-ray generated ions with the heavy \nneutral species, which we refer to as chemical heating. In \nmolecular regions, chemical heating dominates and can account for\n 50 per cent of the energy expended in the creation of an ion pair.\n The heating per ion pair ranges in the limit of negligible \nelectron fraction from about 4.3 eV for diffuse atomic gas, to \nabout 13 eV for the moderately dense regions of molecular clouds \nand to about 18 eV for the very dense regions of protoplanetary \ndisks. An important general conclusion of this study is that \ncosmic-ray and X-ray heating depends on the physical properties of \nthe medium, i.e., on the molecular and electron fractions, the \ntotal density of hydrogen nuclei, and to a lesser extent on the \ntemperature. It is also noted that chemical heating, the dominant \nprocess for cosmic-ray and X-ray heating, plays a role in UV \nirradiated molecular gas. \n}}}",
    "reporter": "gary",
    "cc": "",
    "resolution": "",
    "time": "2012-08-06T13:16:12Z",
    "component": "chemical network",
    "summary": "chemical heating, cosmic rays, and molecular gas",
    "priority": "good to do",
    "keywords": "",
    "version": "trunk",
    "milestone": "no milestone",
    "owner": "nobody",
    "type": "physics"
}

[cloudy-bot]

@CloudyLex changed description from:

we should look into this

Title:    
  Cosmic-ray and X-ray Heating of Interstellar Clouds and Protoplanetary Disks
Authors:  
  Glassgold, Alfred E.; Galli, Daniele; Padovani, Marco
Publication:  
  eprint arXiv:1208.0523
Publication Date: 
  08/2012
Origin:   
  ARXIV
Keywords: 
  Astrophysics - Galaxy Astrophysics
Comment:  
  39 pages, accepted for publication in the Astrophysical Journal
Bibliographic Code:   
  2012arXiv1208.0523G
Abstract
Cosmic-ray and X-ray heating are derived from the electron energy loss calculations of Dalgarno, Yan and Liu for hydrogen-helium gas mixtures. These authors treated the heating from elastic scattering and collisional de-excitation of rotationally excited hydrogen molecules. Here we consider the heating that can arise from all ionization and excitation processes, with particular emphasis on the reactions of cosmic-ray and X-ray generated ions with the heavy neutral species, which we refer to as chemical heating. In molecular regions, chemical heating dominates and can account for 50 per cent of the energy expended in the creation of an ion pair. The heating per ion pair ranges in the limit of negligible electron fraction from about 4.3 eV for diffuse atomic gas, to about 13 eV for the moderately dense regions of molecular clouds and to about 18 eV for the very dense regions of protoplanetary disks. An important general conclusion of this study is that cosmic-ray and X-ray heating depends on the physical properties of the medium, i.e., on the molecular and electron fractions, the total density of hydrogen nuclei, and to a lesser extent on the temperature. It is also noted that chemical heating, the dominant process for cosmic-ray and X-ray heating, plays a role in UV irradiated molecular gas. 

to:

we should look into this

Title:    
  Cosmic-ray and X-ray Heating of Interstellar Clouds and Protoplanetary Disks
Authors:  
  Glassgold, Alfred E.; Galli, Daniele; Padovani, Marco
Publication:  
  eprint arXiv:1208.0523
Publication Date: 
  08/2012
Origin:   
  ARXIV
Keywords: 
  Astrophysics - Galaxy Astrophysics
Comment:  
  39 pages, accepted for publication in the Astrophysical Journal
Bibliographic Code:   
  2012arXiv1208.0523G
Abstract
Cosmic-ray and X-ray heating are derived from the electron energy 
loss calculations of Dalgarno, Yan and Liu for hydrogen-helium gas 
mixtures. These authors treated the heating from elastic scattering 
and collisional de-excitation of rotationally excited hydrogen 
molecules. Here we consider the heating that can arise from all 
ionization and excitation processes, with particular emphasis on 
the reactions of cosmic-ray and X-ray generated ions with the heavy 
neutral species, which we refer to as chemical heating. In 
molecular regions, chemical heating dominates and can account for
 50 per cent of the energy expended in the creation of an ion pair.
 The heating per ion pair ranges in the limit of negligible 
electron fraction from about 4.3 eV for diffuse atomic gas, to 
about 13 eV for the moderately dense regions of molecular clouds 
and to about 18 eV for the very dense regions of protoplanetary 
disks. An important general conclusion of this study is that 
cosmic-ray and X-ray heating depends on the physical properties of 
the medium, i.e., on the molecular and electron fractions, the 
total density of hydrogen nuclei, and to a lesser extent on the 
temperature. It is also noted that chemical heating, the dominant 
process for cosmic-ray and X-ray heating, plays a role in UV 
irradiated molecular gas. 

[cloudy-bot]

@CloudyLex commented:

Hard to say. After one pass through the paper, I'm not even remotely sure they're talking about the same thing I was talking about.

Cheers, Ryan

On Aug 6, 2012, at 9:06 AM, Gary J. Ferland wrote:

this was on the arxiv last friday - he says chemical heating is quite important. this should automatically have been included in what Ryan discussed in Athens. Are his results consistent with this? Gary

[cloudy-bot]

@peter-van-hoof-noaccount changed milestone from "" to "no milestone"