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Single‐ and multi‐pulse blue corona discharges are frequently observed in thunderstorm clouds. Although we know they often correlate with Narrow Bipolar Events (NBEs) in Very Low Frequency/Low Frequency radio signals, their physics is not well understood. Here, we report a detailed analysis of different types of blue corona discharges observed by the Atmosphere‐Space Interactions Monitor during an overpass of a thundercloud cell nearby Malaysia. Both single‐ and multi‐pulse blue corona discharges were associated with positive NBEs at the top of the cloud, reaching about 18 km altitude. We find that the primary pulses of multi‐pulse discharges have weaker current moments than the single‐pulse discharges, suggesting that the multi‐pulse discharges either have shorter vertical channels or have weaker currents than the single‐pulse discharges. The subsequent pulse trains of the multi‐pulse discharges delayed some milliseconds are likely from horizontally oriented electrical discharges, but some NBEs, correlated with both single‐and multi‐pulse discharges, include small‐amplitude oscillations within a few microseconds inside their waveforms, which are unresolved in the optical observation and yet to be understood. Furthermore, by jointly analyzing the optical and radio observations, we estimate the photon free mean path at the cloud top to be ∼6 m. Plain Language Summary: Recent studies indicate that the blue corona discharges detected by the Atmosphere‐Space Interactions Monitor onboard the international space station have close association with a special type of intracloud discharges named Narrow Bipolar Events (NBEs). In this study, we present a detailed analysis of different types of NBE‐associated corona discharges detected by both optical and radio observations. All the detected corona discharges are found to be associated with unusual high‐altitude positive NBEs, which located a few kilometers below the cloud top where the cloud droplets have low impact on the optical observation. This allowed us to infer the physical properties of them and their parent thundercloud by using theoretical models. The results can provide important reference to further investigate the physical mechanism of corona discharge and their role in lightning initiations. Key Points: Corona discharges are found to be associated with unusual high‐altitude positive narrow bipolar events nearby cloud topCorona discharges are classified into different types according to their different optical and radio featuresThe detailed features of corona discharges and their parent thundercloud are estimated using different theoretical models [ABSTRACT FROM AUTHOR]

How lightning initiates inside thunderclouds remains a major puzzle of atmospheric electricity. By monitoring optical emissions from thunderstorms, the Atmosphere‐Space Interactions Monitor (ASIM) onboard the International Space Station is providing new clues about lightning initiation by detecting Blue LUminous Events (BLUEs), which are manifestations of electrical corona discharges that sometimes precedes lightning. Here we combine optical and radio observations from a thunderstorm near Malaysia to uncover a new type of event containing multiple optical and radio pulses. We find that the first optical pulse coincides with a strong radio signal in the form of a Narrow Bipolar Event (NBE) but subsequent optical pulses, delayed some milliseconds, have weaker radio signals, possibly because they emanate from a horizontally oriented electrical discharges which does not trigger full‐fledged lightning. Our results cast light on the differences between isolated and lightning‐initiating electrical discharges. Plain Language Summary: One of the biggest mysteries in the atmospheric sciences is to understand how lightning is initiated inside thunderclouds. By combining observations in optical and radio bands, our work uncovers a yet‐unreported type of lightning process: multi‐pulse corona discharges. For the first time, we cast light on the differences between the isolated and lightning‐initiating electrical discharges. Our results indicate that there is an unexpected class of horizontally oriented electrical discharges between those that are fully isolated and those that initiate a leader. They have been ignored by all the radio observations so far due to their weak radio signals. However, this would be the class of electrical discharges that play a significant role in the initiation of the lightning leaders. Key Points: Optical multi‐pulse corona discharges coincide with Narrow Bipolar Events and their subsequent pulsesSubsequent optical pulses are related to horizontally oriented electrical discharges which sometimes emit weak radio signalsThe class of horizontally oriented electrical discharges might play a significant role in the initiation of the lightning leaders [ABSTRACT FROM AUTHOR]