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Physical Sciences and Mathematics Commons

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College of Saint Benedict and Saint John's University

Physics Faculty Publications

2008

Articles 1 - 2 of 2

Full-Text Articles in Physical Sciences and Mathematics

Observations Of Neutral Depletion And Plasma Acceleration In A Flowing High-Power Argon Helicon Plasma, C. Mark Denning, Matt Wiebold, John E. Scharer Jul 2008

Observations Of Neutral Depletion And Plasma Acceleration In A Flowing High-Power Argon Helicon Plasma, C. Mark Denning, Matt Wiebold, John E. Scharer

Physics Faculty Publications

Neutral depletion effects are observed in a steady-state flowing argon helicon plasma with a magnetic nozzle for high rf input powers (up to 3 kW). Noninvasive diagnostics including 105 GHz microwave interferometry and optical spectroscopy with collisional-radiative modeling are used to measure the electron density (ne), electron temperature (Te), and neutral density (nn). A region of weak neutral depletion is observed upstream of the antenna where increasing rf power leads to increased electron density (up to ne = 1.6×1013 cm-3) while Te remains essentially constant and …


Rabi Oscillations Between Ground And Rydberg States With Dipole-Dipole Atomic Interactions, Todd A. Johnson, E. Urban, T. Henage, L. Isenhower, D. D. Yavuz, T. G. Walker, M Saffman Mar 2008

Rabi Oscillations Between Ground And Rydberg States With Dipole-Dipole Atomic Interactions, Todd A. Johnson, E. Urban, T. Henage, L. Isenhower, D. D. Yavuz, T. G. Walker, M Saffman

Physics Faculty Publications

We demonstrate Rabi oscillations of small numbers of 87Rb atoms between ground and Rydberg states with n≤43. Coherent population oscillations are observed for single atoms, while the presence of two or more atoms decoheres the oscillations. We show that these observations are consistent with van der Waals interactions of Rydberg atoms.