1 / 15

Non-LTE Modeler’s View of Partial Hydrogen Ionization in Solar Plasma Atmosphere

Explore dynamic solar flares, prominence models, and non-equilibrium ionization with MALI code. Learn about ionization equilibrium in various plasma states from simulations and research studies.

richardelliott
Download Presentation

Non-LTE Modeler’s View of Partial Hydrogen Ionization in Solar Plasma Atmosphere

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Partial ionization of hydrogen plasma in the solar atmosphereNon-LTE modeler’s view P. Heinzel Astronomical Institute, Czech Academy of Sciences

  2. Partial hydrogen ionization in a dynamicchromosphere Carlsson and Stein 2002, ApJ 572, 626 SeealsonewsimulationswithBifrost: Martínez-Sykora et al. 2015, Phil. Trans. R. Soc. A 373: 20140268 Martínez-Sykora et al. 2017, ApJ 847:36

  3. Dynamic solarflares Flarix RHD code RADYN RHD code Heinzel 1991, Sol. Phys. 135, 65 Kašparová 2009, A&A 499, 923 Allred et al. 2015, ApJ 809, 104

  4. Prominence non-LTE modelswith AD Fontenla+ 1996

  5. NLTE prominence models 2D 1D Heinzel 2016 and Labrosse 2016 (in Solar Prominences, Springer)

  6. MALI NLTEtransfer code • 1D/2D-slab geometry (MALI1D/MALI2D) – Heinzel 2016 • isothermal-isobaric slabs, generalization to PCTR • height-velocity dependent radiative boundary conditions (including photoionization by external radiation) • multilevel hydrogen atom with continuum (ionization) • other species like CaII and MgII • coupled radiative transfer + statistical equilibrium • fast numerical solution using the ALI techniques • Non-equilibrium ionization of hydrogen with the MALI code

  7. NLTE modeling ofpartial hydrogen ionization • Input: T, p, D, vnt, H, vflow • Output: ne , nHI, radiative and collisionalrates, relaxationtimes • Prominence or a CME-coreisapproximated by a 1D/2D slabmodels (L-alpha line isoptically very thick in prominences, mostlythin in CMEs) • Wesolvetheradiative transfer and statistical-equilibriumequations for a 5-level + continuum hydrogen atom

  8. MALI2D MALI1D Heinzel et al. 2015, A&A 579, A16 Jejčič et al. 2014, Sol. Phys. 289, 2487

  9. Gridofmodelsfromcooleruptiveprominences to hotter CME cores • T-range: 10 000 – 100 000 K • p-range: 0.001 – 1.0 dyn cm-2 • D: 5000 and 50 000 km • vt: 5 km s-1 • H: 350 000 km • zeroflowvelocity (no Doppler effects in the continua) Heinzel and Jejčič 2019, in preparation

  10. Histogram of the kinetic temperature (39) (30) Heinzel+ 2016, Jejčič+2017, Susino+ 2018

  11. Photoionizationisnegligiblefor T > 50 000 K, wherehydrogen ionizationequilibriumisconsistentwith CHIANTI orArnaud & Rothenflug (1985); dependsonly on T For T < 50 000 K, photoionizationstarts to beimportant, and namelyatlow T between 10 000 – 30 000 K wherethesituationbecomes very complex

  12. Herewe show thepartial hydrogen ionization as functionofelectrondensity Variationswith T show againthatfor T > 50 000 K theionizationdegree doesn‘tdepend on theelectrondensity, whileforlower T itdoes. Namelybetween 10 000 and 20 000 K theeffectisimportant

  13. RU and CU are thephotoionization and collisionalratesfromthegroundstateof hydrogen. Weseehowthey vary with T and p. At lowpressures, thephotoionizationrates are fixed by the incident continuumradiation (prominence illuminationfromthesolar disk, atgiven H). At higherpressures, RU rates are higherdue to theintrinsic L-continuumradiation

  14. Kinetic equilibrium for processes 1 <-> k (in general we have 5 eqs. for a 5 level H atom) Special case of ionization equilibrium: Relaxationtime: t = 1 / ( Pk1+ P1k )

  15. T(K) in unitsof 10 000 K Estimatedrelaxationtimesrequired to achievetheionizationequilibriumfrom perturbed plasma states (e.g. T and/or p timevariations). At hightemperaturestherelaxationis very fast, attypical CME-corepressurest_relax < 10 sec. Undercool prominence conditionst_relaxcanreach 1000 sec (alsoseeEngvold 1980, Sol. Phys. 67, 351)

More Related