Stuart Loch
Physics
Professor

Research Areas: Theoretical Atomic Physics

Office: Leach Science Center 2106

Address:
380 Duncan Drive
Auburn, AL 36849

Phone: (334) 844-5154
E-Mail: loch@physics.auburn.edu

Research Page

Education

Professional Employment

Honors and Awards

Professional Activities

Referee: Physical Review A, Atomic Data and Nuclear Data Tables, Journal of Physics B

Reviewer: DOE (Fusion Energy Science), NASA (ARPA Lab Astrophysics Program)

Member: American Physical Society, Institute of Physics (IOP) London

Research and Teaching Interests

My research approach is inherently collaborative. The aim is to generate high quality atomic data for use in fusion and astrophysics. A central part of this is to be involved in the use of the data in analysis of real plasma experiments. Thus, myself and the other theoretical atomic physicists at Auburn have collaborations with a range of experimental groups. This has been further strengthened through the joint faculty position with ORNL. We collaborate with atomic physics experimentalists, to help benchmark the fundamental cross sections that we generate. The atomic data is then processed into a form most useful for modelers. We collaborate with fusion plasma researchers who use the data for diagnostics and modeling of their experiments, and with astrophysics researchers, who use our data for spectral diagnostics. It is my belief that there is much benefit to be obtained from being able to both generate fundamental atomic data and process it into the form of most use in plasma modeling. Along with collaborators at Auburn, Rollins College (FL), the University of Strathclyde (UK) and the JET tokamak (UK), I am part of a program to update the atomic data for use in fusion and astrophysics. This is largely done through the Atomic Data and Analysis Structure (ADAS) suite of codes (www.adas.ac.uk). My research is split into three main areas: (1)Atomic data generation. Using state-of-the-art atomic physics codes, myself and collaborators are working on updating the atomic data used in fusion and astrophysics. The fundamental data is processed into temperature and density dependent coefficients known as generalized collisional radiative coefficients (GCR). To give a few examples of current projects: 1.We recently completed data for H, He, Li, Be and B. We are currently completing the GCR data for C. 2.We have also been working on improving the atomic data for complex species such as tungsten, which is to be used in the divertor strike points of the ITER experiment, currently under construction in France. I am working on improving the atomic data used for W and Mo. 3.I have started a new project aimed at calculating meaningful error bars on atomic data and processing these errors through to spectral predictions, in collaboration with Mike Witthoeft at the Goddard Space Flight Center (GSFC). As far as I know no-one has developed a systematic approach to putting meaningful error bars on theoretical atomic data. (2)Support of fusion plasma experiments. Much of the atomic data that we make is for use in fusion plasma diagnostics/simulations, through spectral diagnostics or impurity transport modeling. (3)Astrophysical applications. Recent X-ray spectral observations of local bright supernovae remnants tentatively identified emission from Mn and Cr. However, the atomic data necessary to interpret these observations was not present. So I am currently generating atomic data for Cr, Mn, Co and Ni, in direct support of these experiments. We have finished generating electron-impact excitation data for the Hlike ions and are almost finished the He-like data. The data will be used to analyze X-ray spectra from the XMM-Newton and Suzaku telescopes, in collaboration with researchers at the GSFC.

Selected Publications

1. Electron-impact ionization moderately charged xenon ions M.S. Pindzola, S.D. Loch, A. Borovik, M.F. Gharaibeh, J.K. Rudolph, S. Schippers, A. Muller, J. Phys. B 46 215202 (2013)
2. Kinetic theory and atomic physics corrections for determination of ion velocities from charge-exchange Spectroscopy J.M. Munoz Burgos, K.H. Burrell, W.M. Solomon, B.A Grierson, S.D. Loch, C.P. Balance, and C. Chrystal Nuclear Fusion 53 093012 (2013)
3. Experimental rate coefficients of F5+  recombining into F4+ S. Ali, I. Orban, S. Mahmood, S.D. Loch, and R. Schuch Astronomy and Astrophysics 557 A2 (2013)
4. Evaluation of an improved atomic data basis for carbon in UEDGE emission modeling for L-mode plasmas in DIII-D J.M. Munoz Burgos, A.W. Leonard, S.D. Loch, and C.P. Balance Journal of Nuclear Materials 438 S406 (2013)
5. Electron-impact excitation and ionization of W3+  for the determination of tungsten influx in a fusion plasma C.P. Ballance, S.D. Loch, M.S. Pindzola, and D.C. Griffin J. Phys. B 46 055202 (2013)