# Revisiting the Stark Width and Shift of He II Pα

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## Abstract

**:**

## 1. Introduction

## 2. Experiment

#### 2.1. Experimental Setup

#### 2.2. Experimental Data

## 3. Code Comparison

#### 3.1. Description of Participating Codes

#### 3.2. Code Results in Model Cases

#### 3.3. Experimental Stark Shift and Simulation Results

## 4. Discussion

## 5. Conclusions

## Author Contributions

## Acknowledgments

## Conflicts of Interest

## References

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**Figure 2.**(

**a**) Spectral image of the time and space integrated He II P$\alpha $ line, (

**b**) sketch of different stages of the compressing plasma channel, and (

**c**) spatially (along x) integrated intensity profiles originating at different times from the compressing plasma channel and the time-integrated profile (the thick gray line).

**Figure 3.**(

**a**) Spectral lineouts at different y positions; (

**b**) spectral lineout at $y=1.5\phantom{\rule{0.166667em}{0ex}}\mathrm{mm}$ and (

**c**) at $y=0$ with their best fits.

**Figure 4.**Experimentally obtained width and shift. The results from the present study are compared to different data from the literature.

**Figure 5.**Sub-cases without quenching. Plasma conditions assumed as follows: (

**a**) ${n}_{e}={10}^{18}\phantom{\rule{0.166667em}{0ex}}{\mathrm{cm}}^{-3}$ and $T=4\phantom{\rule{0.166667em}{0ex}}\mathrm{eV}$; (

**b**) ${n}_{e}={10}^{18}\phantom{\rule{0.166667em}{0ex}}{\mathrm{cm}}^{-3}$ and $T=10\phantom{\rule{0.166667em}{0ex}}\mathrm{eV}$; (

**c**) ${n}_{e}={10}^{19}\phantom{\rule{0.166667em}{0ex}}{\mathrm{cm}}^{-3}$ and $T=4\phantom{\rule{0.166667em}{0ex}}\mathrm{eV}$; (

**d**) ${n}_{e}={10}^{19}\phantom{\rule{0.166667em}{0ex}}{\mathrm{cm}}^{-3}$ and $T=10\phantom{\rule{0.166667em}{0ex}}\mathrm{eV}$.

**Figure 6.**Sub-cases with quenching. Plasma conditions assumed are as follows: (

**a**) ${n}_{e}={10}^{18}\phantom{\rule{0.166667em}{0ex}}{\mathrm{cm}}^{-3}$ and $T=4\phantom{\rule{0.166667em}{0ex}}\mathrm{eV}$; (

**b**) ${n}_{e}={10}^{18}\phantom{\rule{0.166667em}{0ex}}{\mathrm{cm}}^{-3}$ and $T=10\phantom{\rule{0.166667em}{0ex}}\mathrm{eV}$; (

**c**) ${n}_{e}={10}^{19}\phantom{\rule{0.166667em}{0ex}}{\mathrm{cm}}^{-3}$ and $T=4\phantom{\rule{0.166667em}{0ex}}\mathrm{eV}$; (

**d**) ${n}_{e}={10}^{19}\phantom{\rule{0.166667em}{0ex}}{\mathrm{cm}}^{-3}$ and $T=10\phantom{\rule{0.166667em}{0ex}}\mathrm{eV}$.

**Figure 7.**Calculated Stark shift per electron density of ${10}^{18}\phantom{\rule{0.166667em}{0ex}}{\mathrm{cm}}^{-3}$ as a function of plasma temperature. Solid lines: ${n}_{e}={10}^{18}\phantom{\rule{0.166667em}{0ex}}{\mathrm{cm}}^{-3}$; dashed lines: ${n}_{e}={10}^{19}\phantom{\rule{0.166667em}{0ex}}{\mathrm{cm}}^{-3}$.

**Figure 9.**The influence of quenching on the Stark width (

**a**) and shift (

**b**), as calculated by SimU, assuming $T=4\phantom{\rule{0.166667em}{0ex}}\mathrm{eV}$.

y position (mm) | ${\mathit{w}}_{\mathbf{ref}}$ (Å) | ${\mathit{w}}_{\mathbf{shifted}}$ (Å) | ${\mathit{d}}_{\mathbf{shifted}}-{\mathit{d}}_{\mathbf{ref}}$ (Å) |
---|---|---|---|

−1.0 | 2.6 ± 0.1 | 20.8 ± 3.1 | 1.8 ± 1.0 |

−0.8 | 4.0 ± 0.5 | 23.6 ± 2.8 | 2.2 ± 0.6 |

−0.5 | 2.9 ± 0.5 | 28.7 ± 2.4 | 2.9 ± 0.5 |

−0.2 | 3.0 ± 0.7 | 38.1 ± 3.8 | 3.8 ± 0.8 |

0.0 | 2.6 ± 0.7 | 35.9 ± 5.3 | 3.2 ± 1.1 |

0.1 | 2.4 ± 0.6 | 37.8 ± 5.5 | 3.0 ± 1.1 |

0.3 | 2.5 ± 0.5 | 35.0 ± 4.0 | 3.0 ± 0.8 |

0.5 | 2.3 ± 0.5 | 29.0 ± 4.0 | 2.7 ± 0.9 |

Reference | Plasma Source | Working Gas | Observation Direction |
---|---|---|---|

Present data | Gas liner z-pinch | He | Radial |

Büscher et al. [6] | Gas liner z-pinch | H with He doping | Radial |

Fleurier and Gall [2] | Capillary z-pinch | He | Axial |

Gawron et al. [5] | Gas liner z-pinch | H with He doping | N/A |

Kobilarov et al. [4] | Capillary z-pinch | He | Axial |

Pittman and Fleurier [3] | Capillary z-pinch | He | Axial |

Code | Type | Quenching | Reference |
---|---|---|---|

ER | Simulation | No | [13] |

MD | Simulation | No | [14] |

MELS | Model | Yes ${}^{a}$ | [15] |

PPP | Model | No | [16] |

QC-FFM | Model | No | [17] |

SimU | Simulation | Yes ${}^{a}$ | [8] |

ST | Model | Yes | [18] |

Code | Levels | Microfields | Electrons | Ion Dynamics |
---|---|---|---|---|

MELS | Detailed | APEX [22] | Relaxation impact [23] | BID [24] |

PPP | Detailed | APEX | Standard theory impact | FFM [25] |

QC-FFM | QC [26] | Pfennig and Trefftz [27] | FFM w/ impact corr. [17] | FFM w/impact corr. |

ST | Detailed | Tighe and Hooper [20] | K-matrix impact | – |

**Table 5.**Details of participating simulations. In all three codes, the motion of all plasma particles—electrons and ions—is modeled.

Code | Plasma model | Ion Shielding |
---|---|---|

ER | Debye QP’s, straight paths | By electrons only |

MD | True Coulomb MD | N/A |

SimU | Debye QP’s with explicit RPI | By electrons and ions |

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## Share and Cite

**MDPI and ACS Style**

Stollberg, C.; Stambulchik, E.; Duan, B.; Gigosos, M.A.; González Herrero, D.; Iglesias, C.A.; Mossé, C.
Revisiting the Stark Width and Shift of He II P*α*. *Atoms* **2018**, *6*, 23.
https://doi.org/10.3390/atoms6020023

**AMA Style**

Stollberg C, Stambulchik E, Duan B, Gigosos MA, González Herrero D, Iglesias CA, Mossé C.
Revisiting the Stark Width and Shift of He II P*α*. *Atoms*. 2018; 6(2):23.
https://doi.org/10.3390/atoms6020023

**Chicago/Turabian Style**

Stollberg, Christine, Evgeny Stambulchik, Bin Duan, Marco A. Gigosos, Diego González Herrero, Carlos A. Iglesias, and Caroline Mossé.
2018. "Revisiting the Stark Width and Shift of He II P*α*" *Atoms* 6, no. 2: 23.
https://doi.org/10.3390/atoms6020023