{'fraction_non_alphanumeric': 0.026837806301050177, 'fraction_numerical': 0.026837806301050177, 'mean_word_length': 4.535483870967742, '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}}
Observation of the Coronal Hard X-ray Sources of the 1998 April 23 Flare

We analyzed Hard X-Ray Telescope observations of an X1.2 flare on 1998 April 23. This flare is one of the best examples for studying coronal hard X-ray sources due to the intensity of the emission and the occultation of the footpoints. In this flare, coronal hard X-ray sources composed of both thermal and nonthermal emissions showed complex structure unlike any previously observed. Dominant thermal and nonthermal sources do not come from the same loop-top region. Nonthermal sources include two sources in the low corona (~2.7 × 103 km) and an extended source in the high corona (~5 × 104 km). These observations of nonthermal coronal sources suggest that energetic phenomena occur in the low corona at first, and energized electrons are then injected into a high coronal region.