تقرير
Diagnosing transient ionization in dynamic events
| العنوان: | Diagnosing transient ionization in dynamic events |
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| المؤلفون: | Doyle, J. G., Giunta, A., Madjarska, M. S., Summers, H., O'Mullane, M., Singh, A. |
| سنة النشر: | 2013 |
| المجموعة: | Astrophysics |
| مصطلحات موضوعية: | Astrophysics - Solar and Stellar Astrophysics |
| الوصف: | The present study aims to provide a diagnostic line ratio that will enable the observer to determine whether a plasma is in a state of transient ionization. We use the Atomic Data and Analysis Structure (ADAS) to calculate line contribution functions for two lines, Si IV 1394 A and O IV 1401 A, formed in the solar transition region. The generalized collisional-radiative theory is used. It includes all radiative and electron collisional processes, except for photon-induced processes. State-resolved direct ionization and recombination to and from the next ionization stage are also taken into account. For dynamic bursts with a decay time of a few seconds, the Si IV 1394 A line can be enhanced by a factor of 2-4 in the first fraction of a second with the peak in the line contribution function occurring initially at a higher electron temperature due to transient ionization compared to ionization equilibrium conditions. On the other hand, the O IV 1401 A does not show such any enhancement. Thus the ratio of these two lines, which can be observed with the Interface Region Imaging Spectrograph, can be used as a diagnostic of transient ionization. We show that simultaneous high-cadence observations of two lines formed in the solar transition region may be used as a direct diagnostic of whether the observed plasma is in transient ionization. The ratio of these two lines can change by a factor of four in a few seconds owing to transient ionization alone. Comment: 3 pages, in press A&A |
| نوع الوثيقة: | Working Paper |
| DOI: | 10.1051/0004-6361/201321902 |
| URL الوصول: | http://arxiv.org/abs/1307.8251 |
| رقم الأكسشن: | edsarx.1307.8251 |
| قاعدة البيانات: | arXiv |
| DOI: | 10.1051/0004-6361/201321902 |
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