Modeling Non-Equilbirum Plasma. Adam Foster

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1 Modeling Non-Equilbirum Plasma Adam Foster

2 Definition CIE plasma: a plasma which is in collisional ionization equilibrium NEI plasma: a collisional plasma which is not in CIE

3 Ionization Balance dn ( z) =N e S(z 1 z) N (z 1) dt ( N e S(z z+ 1) + N e α( z z 1) + N H C (z z 1)) N ( z) + N e α( z+ 1 z) N ( z+ 1)+ N H C( z+ 1 z) N ( z+ 1)

4 Ionization Balance dn ( z) =N e S( z 1 z) N ( z 1) dt populating ( N e S ( z z+ 1) + Neα ( z z 1) + NHC ( z z 1) )N ( z) + N e α( z+ 1 z) N ( z+ 1) + N H C ( z+ 1 z) N (z+ 1 ) set dn ( z) =0 dt CIE ionbal: S( z 1 z) N ( z 1)+ α( z+ 1 z) N ( z+ 1)=( N e S(z z+ 1)+ N e α( z z 1)) N (z ) depopulating

5 CIE ionization balance

6 Non-Equilibrium Ionization Needs a source of hot or cold electrons. sudden adiabatic expansion & cooling shock heating Solar Flare Cas A Solar Flare

7 Ionization Balance dn ( z) =N e S( z 1 z) N ( z 1) dt ( N e S ( z z+ 1) + Ne α ( z z 1) + NHC ( z z 1) )N ( z) + N e α( z+ 1 z) N ( z+ 1) + N H C ( z+ 1 z) N (z+ 1 ) d N ( z) ( z) = N e A N dt Solve ionization fraction equations explicitly, see, e.g. matrix eigenvector method (Smith & Hughes 2010).

8 Timescales No difference noted at Net < 107 cm-3s (4 1cm-3) Equilibrium at Net>2x1012cm-3s (60,000 1cm-3)

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11 Part 1 summary NEI plasma can exist over a wide range of timescales. It dramatically changes the set of ions visible in a typical temperature plasma

12 Emitting processes from NEI Plasma

13 Emitting processes from NEI Plasma

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19 Excitation Ionization Recombination

20 Summary of relevant processes X +(z-1) X+z X+(z+1) Direct Ionization Excitation-autoionization Collisional excitation Dielectronic recombination Radiative Recombination

21 Ionizing Plasma Signifiers

22 Ionizing Plasma Signifiers

23 Ionizing Plasma Signifiers

24 Ionizing Plasma Signifiers ionizes

25 Fluorescence Yield Li-like 1s 2s2 Ar~z5 Aa~z2 ~ no fluorescence for light elements Gorczyca Ar ωk = Aa+ Ar

26 Yamaguchi+2014 Line Centroid shifts with Ion

27 Yamaguchi+2014 Line Centroid shifts with Ion

28 Recombining Plasma Line ratio shifts enhanced forbidden line Presence & enhancement of DR satellite lines. Low line intensities, n=3 1 transition reduced

29 Continuum Processes Driven By Brems Ne, Te RRC N 2-photon Nz+, ~Te (z+1)+, Te Ionizing Recombining Notes ~ Enhanced Shape truly representative of current Te Reduced (none) Enhanced Edges appear in recombining plasma ~ no effect ~ no effect Not useful as NEI diagnostic ~ Reduced

30 W49B T_init=3.2keV T_final=1.5keV Net=2x1010cm-3s

31 W49B 20ks SXS simulation RRC

32 NEI Modeling with AtomDB Calculate Ionbal Iion=N+z-1Neεion(Te) Iexc=N+zNeεexc(Te) Sum Spectrum! Irec=N+z+1Neεrec(Te)

33 Back to those processes Excitation Ionization Recombination

34 Show me the data! Level resolved recombination data: Badnell+ Level resolved fluorescence yield data: only for lowest 2-3 levels of some ions Inner shell excitation data: Rare! (Liang for Lilike) Inner shell ionization: Coulomb-Born-Exchange (Beigman 1996). Otherwise... nothing

35 Large scale data generation Fill in the blanks! Large scale FAC runs Inner shell excitation up to n=4 Inner shell ionization creating holes in n=1,2,3 shells Autoionization from all doubly excited levels Database size: 300Mb 18Gb.

36 ~Fe XII Kα Kβ 6keV plasma ~Fe XVII Ni Kα Cr Fe XXV Kδ+ Ionizing Plasma Spectrum

37 Line ratio diagnostics 1s2 2s 1s 2s forbidden line regular ratios Recombine statistically greater 1s 2s 3P1 pop

38 Modeling a Recombining Plasma Ozawa+2009 Ozawa+2009 Quantity Ozawa AtomDB 3.0 kte 1.5keV 1.5keV Fe Ni norm

39 Summary on Features on NEI Real Te can still be obtained from brems. Recombining plasma show RRC egdes Ionizing plasmas will show inner shell heavy ion lines if they are hot enough (kt>2kev) Both ionization and recombination lead to an enhanced forbidden line Much room for improvement on the inner shell atomic data Models are available in XSPEC, SPEX etc.

40 NEI Models in XSPEC Nei: single time, single temperature snapshot emissivity. Rnei: same as vnei, but can specify initial temperature Pshock: Parallel shock. Multiple times in a single temperature Npshock: As pshock, but with separate ion and electron temperatures

41 Plug plug plug The beta4 version of NEI is available on the website. Works in all XSPEC models. Need to download updated beta data.