Constantine Theodosiou (Atomic, Plasma and Computational Physics)

Professor of Physics
Ph.D., 1977, University of Chicago

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The research of Dr. Theodosiou's group focuses on atomic physics (structure, Rydberg states, radiative transitions and photoionization, electronic and ionic collisions with atoms), plasma physics (cold and hot plasmas, kinetic methods, Boltzmann Equation, inductively coupled plasmas, and plasma display panels), and computational physics (partial differential equations, Monte Carlo/particle-in-cell methods, parallel computing).

With the exception of hydrogen, atoms and ions are many-body systems and their structure cannot be exactly determined analytically. We are searching for improved approximation methods, which will reproduce experimental findings, as well as provide theoretical predictions to be tested by experiment at UT and other research centers around the world. Some of the work is done in collaboration with scientists in other institutions or in industry.

Our theoretical findings have been important for comparison with experiment and have occasionally resulted in revisions of previous measurements. Our semi-empirical calculations of atomic transition probabilities and their byproducts, like atomic polarizabilities, of single-valence electron systems are among the most accurate in the literature. Our elastic scattering calculations provide important reference information for plasma simulations. Our kinetic and self-consistent treatment of plasmas, as well as the study of external magnetic field influence on plasmas are state-of-the-art.

Recent publications:

· Y. Sosov and C.E. Theodosiou, “On the complete solutions to the Sturm-Liouville problem,, over a closed interval,” J. Math. Phys. 43, 2831 (2002)

· Y. Sosov and C.E. Theodosiou, “A well known physical boundary value problem for equation requires unusual eigenfunctions,” Amer. J. Phys. 72,185-189 (2004)

· Y. Sosov and C. E. Theodosiou, “Determination of the electric field dependence of effective secondary emission coefficients for He/Xe ions on brass,” J. Appl. Phys. 95, 4385-4388 (2004)

· Kaganovich, O. Polomarov, and C. E. Theodosiou, “Landau damping and anomalous skin effect in low-pressure gas discharges: self-consistent treatment of collisionless heating,” Phys. Plasmas 11, 2399-2410 (2004)

· M. Adibzadeh and C. E. Theodosiou, “Differential, total, and momentum transfer cross sections for elastic scattering of electrons by Ba and Sr atoms,” Phys. Rev. A 70, 052704 (2004)

· V. N. Khudik, A. Shvydky, V. P. Nagorny, and C. E. Theodosiou, “Three-dimensional Monte Carlo/Particle-in-cell simulations of the discharge pulse in an AC-PDP cell,” in 4th Triennial Special Issue of the IEEE Transactions on Plasma Science “Images in Plasma Science,” IEEE Trans. Plasma Sci. 33, 510 (2005)

· O. V. Polomarov and C. E. Theodosiou, and I. D. Kaganovich, “Enhanced collisionless heating in a non-uniform plasma at the bounce resonance condition,” Phys. Plasmas (Letter) 12, 080704 (2005)

· O. V. Polomarov, C. E. Theodosiou, I. D. Kaganovich, B. N. Ramamurthi, and D. J. Economou “Effectiveness of electron-cyclotron and transmission resonant heating in inductively coupled plasmas,” Phys. Plasmas 12, 104505 (2005)

· D. Kaganovich, O. V. Polomarov, and C. E. Theodosiou, “Revisiting anomalous RF field penetration into a warm plasma,” IEEE Trans. Plasma. Sci. 34, 696-717 (2006)

· A. Shvydky, V. N. Khudik, V. P. Nagorny, and C.E. Theodosiou, “Dynamic positive column in long-gap barrier discharges,” J. Appl. Phys. 99, 013303(2006)

· V. N. Khudik, A. Shvydky, and C.E. Theodosiou, “Striations in dielectric barrier discharge systems with a hollow anode,” Phys. Plasmas 13, 034501(2006)

· Shvydky, V. N. Khudik, V. P. Nagorny, and C. E. Theodosiou, “Three-dimensional Monte Carlo/Particle-in-cell studies of anode striations and cathode ionization wave in barrier discharges in AC-PDP cells,” IEEE Trans. Plasma Sci. 34, 878-885 (2006)

· O. V. Polomarov, C. E. Theodosiou, I. D. Kaganovich, D. J. Economou, and B. N. Ramamurthi, “Self-consistent modeling of nonlocal inductively coupled plasmas,” IEEE Trans. Plasma Sci. 34, 767-785 (2006)

· V. N. Khudik, A. Shvydky, and C.E. Theodosiou, “Spreading of discharge plasmas above a cathode covered with a dielectric layer,” Phys. Plasmas 13, 073502 (2006)

· V. N. Khudik, A. Shvydky, and C.E. Theodosiou, “Statistical fluctuations in low-current barrier microdischarges,” IEEE Trans. Plasma Sci. 35, 644-649 (2007)

· V. N. Khudik, A. Shvydky, and C.E. Theodosiou, “Fluctuation dominated dynamics of a Townsend micro discharge,” J. Phys. D: Appl. Phys. 40, 3102-3111 (2007)

· V. N. Khudik and C. E. Theodosiou, “Resonant generation of surface acoustic waves
between moving and stationary piezoelectric crystals,” J. Acoust. Soc. Am. 122 (6), 3405-8 (2007)

· V. N. Khudik, Joel Pendery, A. Shvydky, and C. E. Theodosiou, “Backscattering of secondary electrons to the cathode in the oblique electric field in dielectric barrier discharge systems,” J. Phys. D: Appl. Phys. 41 (11), 115203 (2008).