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A: Fachverband Atomphysik

A 1: Plasma Interactions / Rydberg Atoms

A 1.3: Vortrag

Montag, 2. März 2009, 11:45–12:00, VMP 6 HS-B

Ionization–Recombination Balance in the Cold Rydberg Gas — •Yurii V. Dumin — Max Planck Institute for the Physics of Complex Systems, Dresden, Germany

A well-known property of the cold Rydberg gas (formed, for example, in the magneto-optical traps) is its spontaneous ionization, resulting in ultracold plasmas [1]. Although this phenomenon is commonly treated as individual acts of ionization and recombination, such an approach is hardly appropriate for a sufficiently dense gas, whose Thomson radius exceeds the interparticle distance. Just this situation was implemented recently in the cryogenic gas jets [2]. A more adequate description of such systems should be based on the consideration of multi-particle interactions ab initio. This can be performed in the model of quasi-localized electrons, moving in the effective centrifugal potentials formed by the nearest ions; while influence of the distant particles is treated as a thermal bath with the effective virial temperature [3]. Such an approach enables us to derive the electron partition function, which can be efficiently used to calculate the probabilities of free and captured electronic states, thereby giving the degree of ionization of the strongly-coupled Rydberg plasma.

[1] T.C. Killian et al., Phys. Rep. 449, 77 (2007).

[2] J.P. Morrison et al., Phys. Rev. Lett. 101, 205005 (2008).

[3] Yu.V. Dumin, J. Low Temp. Phys. 119, 377 (2000).