{'fraction_non_alphanumeric': 0.02256317689530686, 'fraction_numerical': 0.0036101083032490976, 'mean_word_length': 5.523529411764706, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Magnetized Features of Sheath and Collection Region of Photodetached Electrons in Negative Ion Measurement

The magnetized features of the sheath and collection region of photodetached electrons (PDE's) are experimentally studied in the linear divertor simulator MAP‐II. The thickness of the electron sheath formed around a cylindrical electrostatic probe is measured by analyzing the variation in the temporal evolution of the laser photodetachment (LPD) signal. The effect of the magnetic field on the electron sheath thickness along the field is revealed by comparing the experimental result to the theoretical thickness derived using the Child‐Langmuir (CL) law. The length of the collection region of PDE's is measured in several magnetized regimes by using the recently developed eclipse‐LPD method. The physical meaning of this collection region is discussed based on the measured electron sheath thickness and the length of the collection region. Finally, the necessary conditions for applying the LPD technique in magnetized plasmas are discussed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)