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Atomic Processes in Spectroscopic modeling and their application to EBIT plasma

Atomic Processes in Spectroscopic modeling and their application to EBIT plasma. Guiyun Liang 梁贵云 National Astronomical Observatories, CAS Beijing, China. AtomDB 2014 workshop, Sep.6-9, Tokyo, Japan. Collaborators. UK APAP network. Gang Zhao Jiayong Zhong Feilu Wang Huigang Wei

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Atomic Processes in Spectroscopic modeling and their application to EBIT plasma

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  1. Atomic Processes in Spectroscopic modeling and their application to EBIT plasma GuiyunLiang梁贵云 National Astronomical Observatories, CAS Beijing, China AtomDB 2014 workshop, Sep.6-9, Tokyo, Japan

  2. Collaborators UK APAP network Gang Zhao JiayongZhong Feilu Wang Huigang Wei Fang Li, Bo Han, Kai Zhang, Xiaoxin Pei Jose R. CrespoLopeza-Urrutia Thomas Baumann Laboratory Astrophysics team Yong Wu

  3. Background Atomic processes in modeling — SASAL EBIT and the EUV spectroscopy Applications to EBIT plasma (1) Density diagnostic (2) Overlap factor between the electron beam and ion cloud (3) Pressure diagnostic in EBIT center Outline

  4. Background Our understanding to universe is from what we observed, e.g. Imaging, spectra, as well as imaging + spectroscopy. • The imaging at different photon energy give information from different regions. • i.e. Optical: Photosphere • UV: Chromosphere • EUV+X-ray: Corona • SDO/AIA: 7 EUV channels (~2-10Å) O’ Dwyer et al. (2010) A&A, Dudiket al. (2014) ApJ

  5. New line identification from Fe IX around 94 filter, improves the response of the AIA/94 channel Dudiket al. (2014) ApJ, Foster & Testa (2011) ApJ

  6. With aid of its high spatial resolution and high time cadence (<10s) of SDO, we can known: 1. temperature structure 2. plasma dynamics for a given region. However, a detailed dynamics (what velocity?) is still from spectroscopy with high spectral resolution, i.e. Hinode/EIS observation. EIS 284Å TRACE 171Å Milligan (2011) ApJ

  7. Solar winds with planetary/cometary atmospheres Observation comet and vernusLisseet al. (1996) Simulation of solar wind ions on Martian, Modolo et al. (2005) What components in solar wind? And/or what velocity of these ions? Spectroscopy Bodewits et al. (2006)

  8. CHIANTI v7 (Solar, UK/USA) AtomDB v2 (Stars/galaxy,etc, CfA) MEKAL ADAS v2 (generalized CR, UK) for fusion plamsa Cloudy Xstar (various photoionized, NASA) MOCASSIN SASAL (EBIT, coronal-like, etc, China) The understanding to observed data depends on underlying models for emitters. Optical thin approximation ionization equilibrium e - Collision Photoionization

  9. Recently, Chianti (v7.3) and AtomDB (v3.0) have been improved a lot by incorporating recent and more accurate atomic data. Landi et al. (2013); Foster et al. (2012)

  10. Fitting to obs. Example: SASAL model Output: emissivity Approx.-coding Atomic data Physics: Liang et al. (2014) ApJ

  11. Radiative decay (Aij) • Excitation (EIE) • Photo-excitation (PE) • Collisional Ionization (CI) • Photoionization (PI) • Charge-exchange (CE) • Radiative recombination (RR) • Dielectronic recombination (DR) Atomic Processes in modeling (SASAL) For different cases (e-collisional, photoionized, CXRec), different processes are included, a hybrid also can be done.

  12. Schrödinger/Dirac equation, many method: Cowan, CIV3, SuperStructure, FAC, HULLAC, Autostructure, Grasp, Hartree-Fock etc. • Structure and radiative decay Online data calculation by using FAC/AS based on pre-defined atomic model (configurations) H-like, He-like, Li-like, Be-like, B-like, F-like, Ne-like, Na-like, Al-like sequences

  13. Atomic structure (level energy、gf value) DE Electron excitation（DW） PI Non-resonant photoionization DR Dielectronic recombination RR Radiative recombination PE Photon excitation AUTOSTRUCTURE usage— S11+ (S XII) Function:RUN=‘’ Badnell JPB, 1986, 19 827; CPC 2011, 182 1528 http://www.apap-network.org

  14. 1. Distorted-wave UCL-DW, LADW, FAC, HULLAC, AS-DW (Badnell, 2011, CPC) 2. R-matrix Breit-Pauli, ICFT (intermediate-coupling frame transformation), DARC, CCC, B-spline Converged CC Electron/Photon ion impact scattering

  15. J r,E R-matrix: dividing space into internal and external regions(Breit-Pauli, ICFT, DARC)

  16. Automation of ICFT R-matrix calculation Developed by Whiteford, and implemented by Witthoeft, Liang and Ballance Analysis package: RAP, IDL routines Results: Figures, tables

  17. Method (ICFT) Atomic model (large CI, computable CC) Parallel calculation (Cluster-64 cores, HPC) EIE for iso-electronic sequence Data available at website http://www.apap-network.org Energy points： 200 000350 000 Partial wave: Jmax = 41, above Jmax, ‘top-up’ proceture Consume time: 1－2 day 49 core／ion Product: 1-3.5 GB/ion

  18. Under UK APAP-network, about 8 iso-electronic sequence data available now

  19. When the resonances included, the effective collision strength is NOT varied smoothly with nuclear number, so ‘interpolation’ is not valid to obtain those missed data

  20. Na-like sequence: 11.8Gb + 0.4 Gb Ne-like sequence: 71.4Gb Li-like sequence: 88.7Gb + 2.7Gb Si X: 481 Mb Fe XIV: 5.6 Gb +1.4 Gb (wo correct) S8+— S11+ : 767 Mb (6.2 Gb) + 475Mb +7.6 Gb + 2.1 Gb Below only effective collision strength available He-like: 4.8 Mb F-like: 6.5 Mb Big Data

  21. Direct ionization, and excitation autoionization • Collisional ionization • Level resolved ionization data are calculated by using FAC for He-like, L-shell, Ne-like iso-electronic sequence ions from Li to Zn with pre-defined atomic model. • For some Si and Feions, a detailed check has been done with available experimental data.

  22. Radiative recombination • Dielectronic recombination • Photoionization The data is from published papers, e.g. APAP, Witthoeft, Nahar’s calculation, Venner’s compilation etc.

  23. Charge exchange Donors: • H (13.61) • He (24.59) • H2 (15.43) • CO (14.10) • CO2 (13.78) • H20 (12.56) • CH4 (12.6) Treatment of CX cross-section: • Default is parameterized Landau-Zener approximation • Collection from published data (RARE!) • Hydrogenic model

  24. Obtain the average energy of captured nl (3d) orbital • Using parameterized MCLZ approximation obtain the nl-manifold CX cross-section • Statistical weight to get the nlJ-resolved cross-section 2s 2p 3d In Hydrogenic model: • Obtain the principle quantum number with peak fraction. • ‘Landau-Zener’ weight as • Statistical weight 2s2 2p (ground) Si10+ projectile Smith et al. (2012)

  25. How about this resultant CX cross-section? Not too bad! Solar Winds Rough data is better than no data available at all for astronomers.

  26. Test by soft x-ray spectroscopy from Comet Because charge-exchange cross-section is a function of recipient velocity. We estimate a velocity of 600km/s, being consistent with that (592km/s) from direct sensor of ACE mission.

  27. A brief illustration of SASAL— Collision (EBIT) Original collision strength/cross-section was stored as post-database for various electron energy distribution, including R-matrix, DW data

  28. Emission at non-equilibrium

  29. Metastable effect • Non-equilibrium

  30. An approximate treatment relative to GCR model in ADAS We obtain the level population without contribution from ionization/recombination, this corresponds to the effective excitation to other metastable levels followed by ionization and/or recombination in GCR model.

  31. Very simple treatment at here with assumption of optical thin • electron excitation • photo-excitation • collision with neutral

  32. The application to Z-pinch measurement reveals it is reliable. • Electron density will shorten the time-scale to equilibrium, e.g.at ne=1018 cm-3，it takes only a few ns.

  33. Features of this model: • An extensive database composed of quantum calculation: • Based on Chianti v7 and our recent calculations, including level energies, and radiative decay rates for HCIs • On-line calculations with ‘quantum’ method for some necessary parameter, including Levels, decay rates, excitation (DW), ionization, autoionization, CX cross-section: • For CX, Multi-channel Landau-Zener with rotational coupling approximation is used, Hydrogenic model are also implemented into the present system. • On-line CTMC calculation for CX cross-section is in plan. • Collection for published data with advanced treatment: • Including R-matrix, Atomic-orbital and/or molecular-orbital close coupling, classical-trajectory Monte-carlo (CTMC) • Graphic interface for user operation and command line for extension with other hydrodynamics models

  34. Electron beam ion trap (EBIT) • Electron beam ion trap has a powerful ability help us to benchmark the model: • Produce ions of a desired charge state Epp et al. (2010) JpB;Beiersdorfer (2003) ARAA

  35. Determine which lines come from which charge stage. • Study emission by selecting specific line formation processes Liang et al. (2009) ApJ; Martínez PhD thesis (2005)

  36. Some peoples in Laboratory astrophysics community try to benchmark theory on laboratory facility. The long debating 3C/3D • Nearly 40 years, the difference between the theory and observation is a hot topic. There are many explanation, such as • Opacity; • Blending of inner-shell excitation of Fe XV ions • Recent measurement by LSLC laser and EBIT demonstrates that this is due to the high ratio of gf values in theory. Really? Bernitt et al. (2012) Nature

  37. EUV spectra measurement in EBIT • Heidelberg FLASH/Tesla EBIT • EUV spectrometer • Grazing grating: 2400l/mm • CCD 2048×2048, 13.5m/pixel • Beam energies: 100 — 3000 eV • Energy step: 10 or 20 eV • Photon energies: 90 — 260 Å • Photon resolution: ~0.3 Å • Pressure: ~ 10-8mbar Epp PhD thesis (2007)

  38. In the global fitting, the profile of ‘evolution curve’ also affect by the relative line ratios of given ion. Our detail model analysis overcome this problem.

  39. EUV spectroscopic application to EBIT Diagnostic to electron density in trap

  40. Line ratios involved emission lines with its upper level is dominantly populated from metastable levels

  41. 2. Overlap factor between e-beam and trapped ions

  42. Symbols with error bars are diagnostic results from He-like spectra at the same trap conditions. So this deviation is due to the different overlap factor? Chen et al. (2004) ApJ

  43. 3. Pressure diagnostic to trap center The central space is very small (55mmx10/3mm) to located a vacuum gauge, and that is separate from other space. What we measured pressure (10-8mbar) represents the value around the chamber wall.

  44. (e,Xq+) refers to the overlap factor between the electron beam and ions with charge of q+, the last term represent a continuous injection of neutrals with density of n0+. Charge-exchange rates depends on the relative velocity (100 eV) of recipient (ions) and donor (neutrals).

  45. The module of charge stage distribution Plasma type: Thermal EBIT EBIT/R with escape PhiBB CXERec

  46. For #Fe1008 measurement, there is total 50 beam energies. By an automatic fitting code, we obtain the observed count by a single run with predefined line-list. Ebeam = 1772 eV

  47. Iobs() = Ai(E)()(, E) Here, Ai(E) is the ionic abundance as a function of beam energy, () is the efficiency of the spectrometer, and (, E) is the line emissivity, where E refers to the beam energy • There is two method to generate the ‘evolution curve’ Ai(E) • Global fitting • Single line fitting • Line emissivity:  ~ (E) or • =AijNj • For resonant lines, the uncertainty of (E) is within 5% • Cascading effect will have <10% contribution for line emissivity.

  48. Adopting global fitting, at each pixel channel and at a given energy,

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