{'fraction_non_alphanumeric': 0.01002865329512894, 'fraction_numerical': 0.0, 'mean_word_length': 5.472222222222222, '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}}
Selective excitation of low frequency drift waves by density modulation and parametric excitation of higher frequency mode.

Excitation of low frequency drift waves in a radial region of a weak density gradient is demonstrated experimentally by strong temporal modulation of the plasma density. Though a parallel electron current can destabilize drift waves throughout the region, we observe mode selection at the resonant location matching the frequency of modulation. Parametric mode-mode interaction among two excited drift modes to destabilize a higher frequency one is reported under the specific condition of the growth rate. Theoretically estimated growth rates fit well with the experiment.