1. Photoionized Plasmas: Connections Between Laboratory and Astrophysical Plasmas David Cohen Swarthmore College Collaboration with R. Mancini, J. Bailey, G. Rochau

2. My background/perspective: Traditional astrophysicist (massive stars, their winds, and x-ray emission) At an undergraduate-only college (1500 students in total; 15 physics majors per class year; >50% to PhD programs) (I have done some work in ICF and lab astro, too)

3. Small liberal arts colleges disproportionately produce students who go on to earn physics PhDs e.g. Bill Goldstein, John Mather are Swarthmore College alumni My own students: Amy Reighard (2001) – Michigan – LLNL Vernon Chaplin (2007) – Caltech Mike Rosenberg (2008) – MIT

4. We study black holes (and neutron stars) by watching material fall onto them Hard x-rays from accretion photoionize surrounding (accreting) material – we need to interpret the spectra Broad (astro) science goals: Compact object and accretion physics Physical conditions in the stellar winds/mass-flows Stellar evolution and populations Astrophysical jets Galactic structure Effect of super-massive black hole “feedback” on large scale structure formation

5. Large Scale Structure of the Universe: Gravity from dark matter And Energy injection from AGN (“feedback”) Millennium simulation

6. High-Mass X-ray Binary (HMXRB): Direct wind accretion onto a stellar mass compact object

7. Active Galactic Nucleus (AGN): accretion onto a ~10 9 M sun black hole M 82 – red is X-ray emission

9. Iron models with same ionization balance – very different emission properties (coronal: left and photoionized: right)

12. Ionization parameter – describes physical conditions  = L/r 2 n (ergs cm s -1 ) Ranges from 100 to 10,000 (cgs units)

13. ASCA (Japan) – state of the art 1999

14. Distribution of plasma vs. ionization parameter Peak at low values indicates high-density clumps

17. Chandra (US) state of the art today Low ionization state satellites – fluorescence in high-density clumps

19. Mauche et al. 2008, “The Physics of Wind-Fed Accretion”

20. DEM of  distribution (combined with modeling): Wind density and inhomogeneity (clumping) Dynamics and accretion Ionization and feedback on the dynamics Broadly: How will this system evolve? When we find other systems with quantitative differences in their x-ray spectra, what can we infer about their physical properties?

21. Extragalactic sources: Active Galactic Nuclei (AGN)

24. Challenges Scaling – e.g. in photoionized sources: Low densities (else collisional); but then equilibration?Low densities (else collisional); but then equilibration? Significant optical depths (else RT effects not accounted for)Significant optical depths (else RT effects not accounted for) Thus, large linear scales – incompatible with the labThus, large linear scales – incompatible with the lab

25. Challenges Systems are integrated: GravityGravity HydroHydro Atomic physicsAtomic physics Excitation/ionization kineticsExcitation/ionization kinetics Radiation transportRadiation transport

26. Obvious astrophysical relevance is easiest to realize and demonstrate when: Measurements are localMeasurements are local Small subset of an integrated problem is probedSmall subset of an integrated problem is probed

27. Photoionization experiments on the Z-Machine

28. 10 18 cm -3 of neon

29. pinch spectrometerview gassupply 1.5  m mylar gas cell

30. pinch spectrometerview gassupply 1.5  m mylar gas cell Side view with second spectrometer – measure recombination spectrum

31. View-factor (VisRad: Prism) model (MacFarlane et al.) constructed by Swarthmore undergraduate, M. Rosenberg

43. Genetic algorithm – forward modeling to extract CSD

44. Complementary: Curve of Growth analysis (in progress)

45. We model the CSD with PrismSpect and with CLOUDY Adjust incident spectrum to match experimental results with simulations

46. We model the CSD with PrismSpect and with CLOUDY Adjust incident spectrum to match experimental results with simulations Both codes reproduce the CSD, but with different radiation fields – the calculated ionization parameters differ by 50%

47. Connections to astrophysics Code benchmarking – what CSD, temperature arise from a given ionization parameter? Atomic physics – wavelengths, line broadening, even line identification

50. Controversy: broad Fe UTA or O K-shell edge?

51. Laboratory Astrophysics Needs wavelengths & oscillator strengths Wind speeds are largely of a few 100 km/s => –Required wavelength accuracy thus < 1/1000 (< 2 - 20 mÅ) Atomic codes hardly achieve such accuracy How reliable are the computed photo-absorption cross sections  ~ f ij ? Courtesy: E. Behar

52. Connections to astrophysics Code benchmarking – what CSD, temperature arise from a given ionization parameter? Atomic physics – wavelengths, line broadening, even line identification

53. Difficulties If lab system is integrated (e.g. hydro important in the photoionization experiments) it’s never in the way that’s relevant to integrated astrophysical problem. Regimes are difficult to match (e.g. densities too high). Timescales and equilibrium. Sociological/communication issues – delivering the information astrophysicists already (know they) want.

54. Needs and future prospects Specifically for photoionization experiments More X-ray power/flux and higher ionization parameters

56. Needs and future prospects Specifically for photoionization experiments More X-ray power/flux and higher ionization parameters More and better diagnostics

58. pinch spectrometerview gassupply 1.5  m mylar gas cell Side view with second spectrometer – measure recombination spectrum

59. Needs and future prospects Specifically for photoionization experiments More X-ray power/flux and higher ionization parameters More and better diagnostics Different materials (e.g. iron, but gaseous ?) Are there relevant experiments that can be done at NIF?

60. XMM-Newton Chandra Launched 2000: superior sensitivity, spatial resolution, and spectral resolution sub-arcsecond resolution

61. XMM-Newton Chandra Both have CCD detectors for imaging spectroscopy: low spectral resolution: R ~ 20 to 50 And both have grating spectrometers: R ~ few 100 to 1000 300 km/s

62. XMM-Newton Chandra The gratings have poor sensitivity… We’ll never get spectra for more than a handful of any particular class of object

63. XMM-Newton Chandra Astro-H (Japan) – high spectral resolution at high photon energies …few years from now: 2 eV at 7 keV (microcalorimeter array) International X-ray Observatory (IXO; US&Europe)… ~ 2020 The Future: Focus on iron K-shell

64. X-ray photoionization experiments are producing results …higher X-ray fluxes (and ionization parameters) are required for direct astrophysical relevance. Conclusions

65. Comments on some other lab astro experiments

68. 38 citations to the Shigemori et al. jets paper…none are traditional astronomy

69. The OP model used in solar research predicts Fe L- shell opacity that is too low at Z conditions 1000 1100 1200 1300 0.2 0.4 0.60.8 h (eV) Red= Z data Blue=OP  2 = 16 Red= Z data Blue=OPAS  2 = 3.7 transmission transmission 0.4 0.6 0.8 OP Rosseland mean is ~ 1.5x lower than OPAS at Z conditions. If this difference persisted at solar conditions, it would solve the CZ problem Courtesy: J. Bailey

70. Some related thoughts

71. Helium heating- cooling balance is very important… …so isolating one element at a time is also problematic.

72. Interesting and relevant systems aren’t always in the HED regime

73. Prinja et al. 1992, ApJ, 390, 266 Velocity (km/s) v ∞ =2350 km/s UV spectrum: C IV 1548, 1551 Å Luminosity (ergs/s) opacity (cm 2 /g) radius

74. 1-D rad-hydro simulation of a massive star wind Radiation line driving is inherently unstable: shock-heating and X-ray emission

75.  Pup Chandra HETGS/MEG spectrum (R ~ 1000 ~ 300 km s -1 ) SiMgNeO Fe H-likeHe-like

76. 1-D rad-hydro simulation of a massive star wind We can study clumping in these winds by watching them be blasted by x-rays from a compact object

77. Swarthmore Spheromak Experiment (SSX) kT ~ 50 eV; n e ~ 10 14 ; B ~ 0.1 T

81. 3D reconnection (lab and solar) one foot tall 5 earth diameters tall

82. Student training and exposure to HED concepts, techniques

83. X-ray photoionization experiments are producing results …higher X-ray fluxes (and ionization parameters) are required for direct astrophysical relevance. Conclusions