### Abstract

We propose a simple analytical expression for the occupation probability of highly excited states in low-density hydrogenic plasmas. This expression is based on the "chemical picture" and is derived by using the Holtsmark field and the saddle-point estimates. We believe that this expression would be a basic model in the chemical picture since ion-ion correlation is neglected and the simple saddle-point estimates are used. If the density of the plasma is low enough and the temperature is high enough, this expression would be a good approximation. If not, this model gives roughly the critical principal quantum number at which bound states disappear and the basic reference numerical values of the occupation probability for quantitative comparison study with numerical results by detailed modeling.

Original language | English |
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Pages (from-to) | 670-672 |

Number of pages | 3 |

Journal | Astrophysical Journal |

Volume | 532 |

Issue number | 1 PART 1 |

Publication status | Published - Mar 20 2000 |

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### Keywords

- Atomic processes
- Plasmas

### ASJC Scopus subject areas

- Nuclear and High Energy Physics
- Space and Planetary Science

### Cite this

*Astrophysical Journal*,

*532*(1 PART 1), 670-672.

**Simple expression of occupation probability in the "chemical picture".** / Nishikawa, Takeshi.

Research output: Contribution to journal › Article

*Astrophysical Journal*, vol. 532, no. 1 PART 1, pp. 670-672.

}

TY - JOUR

T1 - Simple expression of occupation probability in the "chemical picture"

AU - Nishikawa, Takeshi

PY - 2000/3/20

Y1 - 2000/3/20

N2 - We propose a simple analytical expression for the occupation probability of highly excited states in low-density hydrogenic plasmas. This expression is based on the "chemical picture" and is derived by using the Holtsmark field and the saddle-point estimates. We believe that this expression would be a basic model in the chemical picture since ion-ion correlation is neglected and the simple saddle-point estimates are used. If the density of the plasma is low enough and the temperature is high enough, this expression would be a good approximation. If not, this model gives roughly the critical principal quantum number at which bound states disappear and the basic reference numerical values of the occupation probability for quantitative comparison study with numerical results by detailed modeling.

AB - We propose a simple analytical expression for the occupation probability of highly excited states in low-density hydrogenic plasmas. This expression is based on the "chemical picture" and is derived by using the Holtsmark field and the saddle-point estimates. We believe that this expression would be a basic model in the chemical picture since ion-ion correlation is neglected and the simple saddle-point estimates are used. If the density of the plasma is low enough and the temperature is high enough, this expression would be a good approximation. If not, this model gives roughly the critical principal quantum number at which bound states disappear and the basic reference numerical values of the occupation probability for quantitative comparison study with numerical results by detailed modeling.

KW - Atomic processes

KW - Plasmas

UR - http://www.scopus.com/inward/record.url?scp=0034688744&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0034688744&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:0034688744

VL - 532

SP - 670

EP - 672

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 1 PART 1

ER -