Address for correspondence:
Leibniz Institute for Plasma Science and Technology (INP Greifswald)
ICPM-3
Felix-Hausdorff-Str. 2
17489 Greifswald
Germany
Tel.: +49 (0) 3834 554 314
Fax: +49 (0) 3834 554 301
E-Mail: icpm3@inp-greifswald.de