IAEA International Atomic Energy Agency Applications of Atomic Processes Modeling In a Plasma H. K. Chung Atomic and Molecular Data Unit, Nuclear Data Section in collaboration with Y. Ralchenko, M. Chen and R. W. Lee February 17-19, 2010 LULI, COLE POLYTECHNIQUE IAEA Collaborators Theory and Modeling: R. W. Lee, M. H. Chen, H. A. Scott, M. Adams, M. E. Foord, S. J. Moon, S. B. Libby, S. B Hansen, K. B. Fournier, B. Wilson, S. C. Wilks, A. Kemp, R. Town, M. F. Gu, B. McCandless, M. Tabak Experiments: P. Patel, R. Shepherd, C. A. Back, S. Glenzer, J. Koch, G. Gregori, N. Landon, M. Schneider, K. Widmann, J. Dunn, R. Heeter, H. Chen, Y. Ping, M. May, R. Snavely, H-S. Park, M. Key, K. Akli, S. Chen Reference : H.-K Chung, R. W. Lee Applications of NLTE population kinetics High Energy Density Physics 5 (2009) 114 IAEA Outline Motivation NLTE (non-local thermodynamic equilibrium) Kinetics Modeling Applications of NLTE Kinetics Modeling Introduction to IAEA Atomic & Molecular Unit IAEA Advances in plasma generation access new regimes of matter USP: Ultra short pulse laser (RAL, LULI, Titan, Texas) XFEL: X-ray free electron lasers (SLAC, DESY, Spring-8) Pulse Power: X-Pinches, Z-Pinches... (Sandia, Cornell, UNR) NIF (National Ignition Facility) Hotter and denser matterTransient states of matter Warm dense matterAstronomical X-ray applications XFEL IAEA Modeling capabilities essential for high energy density physics Radiation-Hydrodynamics simulations are required to understand transient, non-uniform plasma evolution Fluid treatment of plasma physics - Mass, momentum and energy equations solved Plasma thermodynamic properties (N e, T e, T i, T r, V r, Vi.. ) LTE (Local Thermodynamic Equilibrium) (assumed) PIC simulations provide non-equilibrium electron energy distributions Particle treatment of plasma physics - Boltzmann transport and Maxwell equations solved Electron energy distribution function (f e..) Simple ionization model (assumed) Non-LTE kinetics models provide spectroscopic observables Atomic processes in plasmas - Rate equations are solved for a given electron energy distributions (f e ) Atomic level population distributions Plasma conditions (N e, T e ) (assumed) IAEA Non-Equilibrium Multiple T e Non-LTE kinetics Example: Short-pulse laser-generated plasmas K spectroscopy K- spectral intensity Generated by non-thermal electrons inner-shell ionization of K-shell electrons Shifts and broadening of cold K- Diagnostics of Thermal electrons Charge state distributions (CSD) Spectroscopic observables Plasma characteristics Non-uniform Heating of the front surface Non-local energy deposition (e-) Transient Short-pulse laser interaction Target expansion Opacity effects Spatial gradients Time dependent intensity Hot e- is relaxed to thermal e- (T e, N e ) change with time Time-dependent CSD IAEA Experiments require integrated simulations: Rad-Hydro, Electron transport, and NLTE Kinetics Hydro Code LSP PIC NLTE-Kinetics Code Predicted Spectrum Provides estimate of pre-plasma to PIC PIC sends back hot electron estimates to Hydro. Hydro provides estimate of background electron temperature to NLTE-kinetics codes Determines charge state distribution Experimental Laser/Target conditions Rad. Transport Feedback? (S. Wilks) IAEA Non-LTE kinetics is essential to predict charge state distributions, level populations, radiation intensity Mean ionization states, Charge state distributions (CSD), Spectral intensity, Emissivity, Opacity, Equation of state (EOS), Electrical conductivity require population distributions of ions in the plasma. Energy levels of an atom Continuum Ground state of ion Z Ground state of ion Z+1 B1B1 A3A3 A1A1 A2A2 BOUND-BOUND TRANSITIONS A 1 A 2 +hv 2 Spontaneous emission A 1 +hv 1 A 2 + hv 1 +hv 2 Photo-absorption or emission A 1 +e 1 A 2 +e 2 Collisional excitation or deexcitation BOUND-FREE TRANSITIONS B 1 +e A 2 +hv 3 Radiative recombination B 1 +e A 2 +hv 3 Photoionization / stimulated recombination B 1 +e 1 A 2 +e 2 Collisional ionization / recombination B 1 +e 1 A 3 A 2 +hv 3 Dielectronic recombination (autoionization + electron capture) IAEA FLYCHK Model : simple, but complete Screened hydrogenic energy levels with relativistic corrections Relativistic Hartree-Slater oscillator strengths and photoionization cross- sections (Scofield) Fitted collisional cross-section to PWB approximation Semi-empirical cross-sections for collisional ionization Detailed counting of autoionization and electron capture processes Continuum lowering (Stewart-Pyatt) (n) (nl) (nlj) (detailed-term) FLYCHK HULLAC / FAC / MCDF IAEA Plane-Wave Born approximation for collisional excitation Plane-Wave Born approximation using DHS wave functions and YK Kims threshold scaling (JJATOM) gives reasonable cross-sections Comparison of FAC, HULLAC & JJATOM Comparison of Fit & JJATOM IAEA Application to a wide range of Z and experiments: Excitation autoionization (EA) /Dielectronic recombinationa (DR) processes are modeled with doubly-excited and inner-shell (IS) excited states Promotion of IS electrons can lead to states near the continuum limit and EA/DR process of IS is critical N-shell Ion 3 l 18 4 l z+1 N-shell Ion 3 l 18 4 l z 3 l 17 4 l z nl 3 l 16 4 l z+1 nlnl 3 l 17 4 l z+1 nl High Z atom L-shell Ion 1 s 2 2 l Z+1 L-shell Ion 1 s 2 2 l Z 1 s 1 2 l Z+1 nl Doubly- excited Inner- Shell 1 s 2 2 l Z-1 3 lnl Bound Low Z atom Promotion of IS electrons leads to states far from continuum limit and rarely matters in CSD Bound Doubly- excited Inner- Shell 3 l 18 4l Z-1 5 lnl IAEA Total line emissivity and energy-dependent spectral intensity in the STA formalism Total line emissivity: plots show approximate line emission spectra and provides information on energy range of dominant emission [eVcm 3 /s/atom] Spectral emissivity is computed in the STA formalism using configuration- average atomic data generated by the DHS(Dirac-Hartree-Slater) code (M.Chen) STA width [ergs/s/Hz/cm 3 /ster] IAEA Available to the community at password- protected NIST website: Advantages: simplicity and versatility applicability for fixed any densities: electron, ion or mass Mixture-supplied electrons (eg: Argon-doped hydrogen plasmas) External ionizing sources : a radiation field or an electron beam. Multiple electron temperatures or arbitrary electron energy distributions Optical depth effects Outputs: population kinetics code and spectral synthesis and charge state distribution Radiative Power Loss rates under optically thin assumption Energy-dependent spectral intensity of uniform plasma with a size Caveats: simple atomic structures and uniform plasma approximation Less accurate spectral intensities for non-K-shell lines Less accurate for low electron densities and for LTE plasmas When spatial gradients and the radiation transport affect population significantly IAEA Applications to Plasma Research Short-pulse laser-produced plasmas Arbitrary electron energy distribution function Time-dependent ionization processes K- shifts and broadening: diagnostics Long-pulse laser-produced plasmas Average charge states Spectra from a uniform plasma Gas bag, Hohlraum (H0), Underdense foam Z-pinch plasmas: photoionizing plasmas Proton-heated plasmas: warm dense matter EBIT: electron beam-produced plasmas EUVL: Sn plasma ionization distributions TOKAMAK: High-Z impurities 28eV 36eV 32eV SiO 2 -Ti foam exp Time-dependent Ti K emissivities Tin charge state distributions IAEA Example: Gold ionization balance in high temperature hohlraum (HTH) experiments LASNEX simulation (D. Hinkel) N e /N cr TeTe L-shell gold spectra (K. Widmann) High-T hohlraum reach temperatures: ~ 10 keV Spectrum from n e ~ 4x10 21 cm -3, T e ~ 7-10 keV measured for first time Line of sight IAEA HTH Lower T e than the peak simulated T e : consistent for large and small scale hohlraums FLYCHK gives an estimate of Gold Charge state distributions and L-shell spectra FLYCHK Gold ionization balance FLYCHK gives an estimate of for a wide range of plasma conditions, which is suitable for experimental design and analysis Spectroscopic data and calculation IAEA Example: Cu K radiation measured by single hit CCD spectrometer and 2-D imager for T e diagnostics Single Hit CCD K yield is higher than that of 2-D imager for smaller target volumes : An experimental evidence of shifting and broadening of K emission lines in small targets with high temperatures K yield (photons/Sr/J) At keV Target volume ( ) 500x500x30 100x100x20 100x100x5 100x100x1 IAEA Shifts and Broadening of K emission as a function of electron thermal temperature Target volume ( ) FLYCHK simulations Average T e (eV) of targets 500x500x30 100x100x20 100x100x5 100x100x1 2d spacing uncertainty IAEA Example: Astrophysical Models used for observations can be benchmarked by Laboratory Understanding laboratory data helps understanding astrophysical objects IAEA The ionization parameter characterizes X-ray photoionized plasmas Correct interpretation of X-ray astronomy data relies on atomic modeling of the complex processes in radiation dominated, NLTE regime IAEA Application to photoionized plasmas compares reasonably well with astrophysical models The agreement between measured and calculated CSDs is reasonable at T e = 150 eV: Cloudy: Astrophysics code Galaxy: NLTE kinetics code FLYCHK: NLTE kinetics code =20-25 ergs-cm/s Z-pinch IAEA Example: XFEL provides an opportunity for HEDS plasma spectroscopy Source for hollow ion experiment 0.1 m CH 25 m Mg Visible laser t = 0 laser irradiates CH with Mg dot Photoionization of multiple ion species: K x L y M z +h XFEL K x-1 L y M z +e (x=1,2; y=1-8; z=1,2) Auger Decay of multiple ion species: K x L y M z +h XFEL K x-1 L y M z +e K x L y-2 M z +e Sequential multi-photon ionization: K x L y M z +h XFEL K x-1 L y M z +e+h XFEL K 0 L y M z +e+h XFEL K 0 L y-1 M z +2e +h XFEL K x L y M z +h XFEL K x-1 L y M z +e+h XFEL K x-1 L y-2 M z +2e Direct multi-photon ionization: K x L y M z +2h XFEL K 0 L y M z +2e XFEL spectrometer t > 1 ps XFEL pumps Mg plasma IAEA In Warm Dense Matter regime the hollow ions provide time-resolved diagnostic information XFEL forms unique states and provides in situ diagnostics with ~100 fs res. 5x keV photons in 30 m spot into a n e =10 23 cm -2 plasma Strong coupling parameter, ii = Potential/Kinetic Energy ~ 10 Steady-state Spectra at various T e At high n e emisson lasts ~100 fs IAEA Example: Radiative loss rates are important as an energy loss mechanism of high-Z plasmas Calculated Kr radiative cooling rates per N e [eV/s/atom/cm -3 ] coronal IonHULLAC+DHS Sum 30,851,708 # of radiative transitions using HULK code IAEA FLYCHK radiative loss rates give quick estimates over a wide range of conditions Radiative cooling rates per N e IonHULLAC+DHSFLYCHK sum 30,851, Time ~2 days~mins # of radiative transitions Max~30% Better agreement for higher N e IAEA Activities at IAEA AMD Unit : Databases on Atomic and Molecular Data for Fusion. ALADDINALADDIN The atomic and molecular, plasma-surface interaction database AMBDASAMBDAS The bibliographical database GENIEGENIE A search engine on different databases on the web OPEN-ADASOPEN-ADAS A joint development between the ADAS Project and IAEA Online Computing Heavy Particles collisionsHeavy Particles collisions Cross sections for excitation and charge transfer for collisions Los Alamos atomic physics codesLos Alamos atomic physics codes An interface to run several Los Alamos atomic physics codes Average ApproximationAverage Approximation An average approximation cross sections Rate coefficientsRate coefficients collisional radiative calculations with the Los Alamos modeling codes to obtain total radiated power, average ion charge, and relative ionization populations Coordinated Research Projects Light Element Atom, Molecule and Radical Behaviour in the Divertor and Edge Plasma Regions Characterization of Size, Composition and Origins of Dust in Fusion Devices Data for Surface Composition Dynamics Relevant to Erosion Processes Spectroscopic and Collisional Data for Tungsten from 1 eV to 20 keV NEW KNOWLEDGE BASE LAUNCHED! IAEA International Atomic Energy Agency Future Extensions IAEA More research is needed: K spectroscopy of dense matter in presence of hot electrons FLYCHK uses the minimal set of configurations for NLTE plasmas This leads to inaccurate K emissivity for warm-dense matter(T e 100eV) K 2 L 8 M 18 N 5 (Z=33) Bound K 1 L 8 M 18 N 6 L-shell K-shell K 2 L 8 M 18 N 5 K 2 L 7 M 18 N 6 M-shell K 2 L 8 M 17 N 6 K 2 L 8 M 16 N 7 K 1 L 8 M 16 N 8 K 2 L 8 M 15 N 8 K 2 L 7 M 16 N 8 K 1 L 8 M 18 N 6 Non-LTE plasma view Solid-density matter view K 1 L 8 (MN) 24 K 2 L 7 M 18 N 6 K 2 L 7 (MN) 24 ~400 eV K 1 L 8 M 17 N 7 K 2 L 7 M 17 N 7 IAEA For WDM matter the set of configurations need to be expanded - for this we developed SCFLY FLYCHK is good; but, emissivities are not good for WDM Analysis with limited configuration sets can give higher T e in K diagnostics Silver : and total K emissivities Solid density and N e = cm -3 Hot e - of cm -3 at 1 MeV (K 1 L 6 )M 1 (K 1 L 6 ) Copper : K spectra SCFLY FLYCHK + (K 1 L 6 )M 3 (K 1 L 6 )M 2 N 1 (K 1 L 6 )M 1 N 2 (K 1 L 6 )M 2 (K 1 L 6 )M 1 N 1 IAEA Population kinetics module for plasma simulations with non-Maxwellian electrons Electron thermalization due to elastic collisions with e - and ions Collisional excitation/de-excitation and ionization/recombination Sources such as collisional, photo and Auger electrons Sinks such as 3-body, radiative recombination and e - capture 200 eV-200 fs pulse with E/E~ photons on solid Al 40 spot XFEL test problem Ionization distributions Electron energy distributions Relaxation time scales Assumptions 1)No initial solid-state structure 2)No plasma motion Elastic losses to phonon (deformation potential) scattering Ionization potential depression using quasi-bound states Treatment of extremely fast particles IAEA Preliminary test results: Effect of inelastic processes on the f e (E) relaxation of FEL problem Atomic structure in the solid-density matter make differences in the determination of N e and therefore T e Conduction electrons and bound electrons will play a role in f e (E) evolution 200 eV-200 fs pulse with E/E~ photons on solid Al 40 spot E p =E i +3/2 kT e N e = N i IAEA International Atomic Energy Agency High Energy Density Physics Plasma Generation Devices IAEA A new state of matter achieved experimentally requires new theories and modeling capabilities the strong coupling parameter is ratio of the interaction energy to the kinetic energy is the degeneracy parameter HDM occurs in: Supernova, stellar interiors, accretion disks Plasma devices : laser, ion beam and Z-pinches Directly driven inertial fusion plasmas WDM occurs in: Cores of large planet Systems that start solid and end as a plasma X-ray driven implosion Hydrogen phase diagram (R.W. Lee) IAEA National Ignition Facility (NIF):1.8 MJ-192 beam laser will generate extreme states of matter Laser is focused through hole in holhraum Laser impinges on wall creating a plasma Wall plasma radiates x-rays X-ray are absorbed in the pusher part of sphere Heated material drives a shock DT ice 980 m Be and Cu DT vap or 1140 m 900 m Laser beams hohlraum -T Track of Be pusher and DT fuel DT and Be sample the warm dense matter regime (see yellow bands) The matter is dense with temperatures less than their Fermi energy DT becomes hot dense matter Compression to 10 3 liquid density with T at 10 4 eV (R.W. Lee) IAEA Ultra-short-pulse lasers provide opportunities to study high energy density physics(HEDP) Hot e- transport in materials - fast ignitor - positron production Isochoric Heating - focused proton beams - laser heated foils Laser generated proton radiography - shock imaging, r(x,t), E,B K radiography - shock imaging, r(x,t) - hydro instablities - e- beam diagnostics protons Hot e- IAEA X-ray free-electron lasers are well suited to high-energy density science Ultrashort pulses are useful create HED states of matter probe the highly transient behavior of HED states High photon energy is required heat the target volumetrically and, thus, minimize gradients directly probe the high densities High photon number is useful to make single-shot data feasible Intense (10 12 photons), short pulse (~50 fs), tunable sources (R.W. Lee) Plasma and Warm Dense Matter Studies Atomic Physics Experiments Structural Studies on Single Particles and Biomolecules Femtochemistry Studies of Nanoscale Dynamics in Condensed Matter Physics IAEA Sandia Z machines mimics X-rays from stars: Non-LTE opacity and radiation transport Z Accelerator Z-Backlighter Laser Saturn Accelerator Hermes III Accelerator RHEPP I RITS Accelerator IAEA International Atomic Energy Agency Example: Short-pulse laser-generated plasmas K spectroscopy IAEA Non-Equilibrium Multiple T e Non-LTE kinetics Example: Short-pulse laser-generated plasmas K spectroscopy K- spectral intensity Generated by non-thermal electrons inner-shell ionization of K-shell electrons Shifts and broadening of cold K- Diagnostics of Thermal electrons Charge state distributions (CSD) Spectroscopic observables Plasma characteristics Non-uniform Heating of the front surface Non-local energy deposition (e-) Transient Short-pulse laser interaction Target expansion Opacity effects Spatial gradients Time dependent intensity Hot e- is relaxed to thermal e- (T e, N e ) change with time Time-dependent CSD IAEA Example of Spectroscopic Diagnostics : 5J 500 fs COMET laser on Al/Ti targets X-ray streaked camera at the front side to measure time-dependent Al He and Ti K : highly transient plasma evolution of non- thermal and thermal e- t E Ti-K Al-He Electron energy [keV] Electron spectrometer at the back side measures non-equilibrium electron temperatures Space-resolved time-integrated spectra are collected at the back side to measure non- uniform thermal electron Te distributions Thick Ti Thin Al Ti K- Al K-shell emission Time resolved x-ray spectrometer Schematic diagram IAEA Spectral calculations driven by an expanding plasma relaxation model dont predict data Time-dependent Ti K measurement Spectral calculations at W/cm 2 Why does the emission rise slowly and decrease gradually unlike simulations? IAEA Experiments require integrated simulations: Rad-Hydro, PIC/LSP, and NLTE Kinetics Hydro Code LSP PIC NLTE-Kinetics Code Predicted Spectrum Provides estimate of pre-plasma to PIC PIC sends back hot electron estimates to Hydro. Hydro provides estimate of background electron temperature to NLTE-kinetics codes Determines charge state distribution Experimental Laser/Target conditions Rad. Transport Feedback? (S. Wilks) IAEA Cu slab with prepulse: I = 4x10 12 W/cm 2 12 m FWHM Gaussian on 40 m FWHM ~ 1 nsec T e (eV) z( m) n e (cm 3 ) input to a 1-D PIC code Radiation Hydrodynamics give an estimate of preformed plasma conditions for PIC codes (S. Wilks) IAEA ln f(E) E (in MeV) T e = (in 17 MeV) T e = (in 3 MeV) x (c/ 0 ) Forward SRS in underdense Ponderomotive heating Ponderomotive heating* *kT hot scaling from S. C. Wilks and W. L. Kruer, (Absorption of ultrashort, ultra-intense laser light by Solids and Plasmas, IEEE J. Quant. Elec., ) High intensity laser 1-D PIC simulation predicts multi-MeV electrons (S. Wilks) IAEA LSP simulates realistic targets and times The characteristic kinetic energy of electrons generated by an ultra-intense laser interacting with a foil is roughly given by These electrons couple to the electrons in the solid, and heat the entire solid. (PIC cannot do collisions, Thus we resort to commercial-grade code LSP, a 3-D, everything code. Temp. vs. Laser Intensity r = 300 m 100 m hot e- Fluid e- 1 keV NLTE Physic -> IAEA LSP simulations determine f e (v) at each point in time and space in the ionized material The ionization balance and spectra are calculated using f e (v) and T e in a time-dependent non-LTE model 2 ps (S. Wilks)