{'fraction_non_alphanumeric': 0.023383768913342505, 'fraction_numerical': 0.0, 'mean_word_length': 4.473684210526316, '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}}
Departure from quasilinear heating in a cross-field ion beam experiment

Ion heating by cross-field current-driven ion acoustic turbulence is investigated in a double-plasma device. The spatial heating rate delta U/ delta x of an ion beam is measured as a function of the integrated noise energy density Psi of broadband noise. At the lower values of Psi the observations approximately follow the quasilinear prediction that delta U/ delta x (or delta U/ delta t) varies as Psi tau c where tau c is the autocorrelation time. As Psi approaches its highest observed values, delta U/ delta x reaches saturation. At the transition between the quasilinear and saturation regimes, tau c is of the order of the particle trapping time.