Darmstadt 2008 – scientific programme

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A: Fachverband Atomphysik

A 26: Posters: BECs, ultracold gases and plasmas

A 26.21: Poster

Thursday, March 13, 2008, 16:30–18:30, Poster C3

The Subharmonics of Electron Emission from Ultracold Plasmas: Collective Plasma Oscillations vs. Individual Excitation of Rydberg Atoms — •Yurii V. Dumin and Jan M. Rost — MPI for the Physics of Complex Systems, Dresden

One of the most interesting phenomena revealed recently in the study of ultracold plasma clusters is a series of distinctive peaks in the electron emission from an ultracold plasma subjected to external radio waves [R.S. Fletcher, et al., PRL 96, 105003 (2006)]. An evident interpretation of this effect is the excitation of resonant plasma oscillations. This explanation, however, encounters difficulties in the quantitative description of the higher harmonics. The alternative point of view, which will be discussed in our report, is a resonant perturbation of highly excited Rydberg atoms in the plasma, resulting in the escape of the respective Rydberg electrons from the system. The main advantage of this mechanism is an easy generation of the higher harmonics and their robustness with respect to the geometry and size of the cluster.