Microwave radiation associated with positive narrow bipolar events
In this paper, we examined seven isolated positive Narrow Bipolar Events (NBEs), one positive NBE that initiated an IC flash progressed to a single-stroke Cloud-to-Ground (CG) flash, and one positive NBE that initiated an IC flash. Seven NBEs have been accompanied by significant Very-High Frequency...
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my.uniten.dspace-346982024-10-14T11:21:50Z Microwave radiation associated with positive narrow bipolar events Baharin S.A.S. Ahmad M.R. Sabri M.H.M. Alammari A. Al-Kahtani A.A.N. Lu G. Kawasaki Z. Cooray V. 57206727343 58861819300 57200560218 57217994803 57219739527 12781228700 36916954400 7005428121 Conventional breakdown Fast breakdown Microwave Narrow bipolar event Very-high frequency Integrated circuits Interferometers Microwave sensors Conventional breakdown Fast breakdown High-frequency radiation Leadtime Narrow bipolar events Radiation pulse Radiation source Single stroke Total length Very high frequency Antennas In this paper, we examined seven isolated positive Narrow Bipolar Events (NBEs), one positive NBE that initiated an IC flash progressed to a single-stroke Cloud-to-Ground (CG) flash, and one positive NBE that initiated an IC flash. Seven NBEs have been accompanied by significant Very-High Frequency (VHF) and microwave radiation pulses. We recorded all NBEs from two measurement stations (ST1 and ST2) separated at 13.3 km apart which consisted of fast antenna (FA) and slow antenna (SA) sensors, a magnetic field (B-field) sensor, a VHF sensor (60 MHz), and a microwave sensor (0.97 GHz). The waveforms were sampled at 2.5 GHz (400 ps). The key finding is that all microwave radiation pulses have been found to precede both the VHF radiation pulses and NBEs with average lead time of 63 � 39 ns and 122 � 143 ns, respectively. In comparison to stepped leader pulses or SLPs (conventional breakdown), the average lead time of microwave to VHF for NBEs (fast breakdown) was 88% faster compared to the average lead time of microwave to VHF for SLPs. Moreover, the average lead time of VHF to NBEs was 56% faster when compared to the average lead time of VHF to SLPs. The VHF interferometer map for an isolated NBE (NBE6) showed upward propagation of VHF radiation sources (fast negative breakdown) with initiation altitude, total length of the VHF radiation sources propagation, and estimated velocity were 10.2 � 0.3 km, 2.9 � 0.6 km, and 1.8 � 108 and 2.8 � 108 ms?1, respectively. On the other hand, interferometer map for an NBE that initiated a single-stroke CG (NBE3) showed bidirectional fast streamers propagation with initiation altitude, total length of the VHF radiation sources propagation, and estimated velocity were 14.0 � 0.4 km, 2.9 � 0.82 km, and 1.6 � 108 and 2.8 � 108 ms?1, respectively. Clearly, the microwave and VHF radiation pulses associated with positive NBEs have been emitted by different processes of fast breakdown mechanism. Therefore, it can be suggested that the microwave radiation is emitted by electron avalanches/corona while the VHF radiation is emitted by fast propagating streamers. � 2022 Elsevier Ltd Final 2024-10-14T03:21:50Z 2024-10-14T03:21:50Z 2023 Article 10.1016/j.jastp.2022.105998 2-s2.0-85144385241 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85144385241&doi=10.1016%2fj.jastp.2022.105998&partnerID=40&md5=78d6f3e37de5fadb775905bc90951e1e https://irepository.uniten.edu.my/handle/123456789/34698 242 105998 Elsevier Ltd Scopus |
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Conventional breakdown Fast breakdown Microwave Narrow bipolar event Very-high frequency Integrated circuits Interferometers Microwave sensors Conventional breakdown Fast breakdown High-frequency radiation Leadtime Narrow bipolar events Radiation pulse Radiation source Single stroke Total length Very high frequency Antennas |
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Conventional breakdown Fast breakdown Microwave Narrow bipolar event Very-high frequency Integrated circuits Interferometers Microwave sensors Conventional breakdown Fast breakdown High-frequency radiation Leadtime Narrow bipolar events Radiation pulse Radiation source Single stroke Total length Very high frequency Antennas Baharin S.A.S. Ahmad M.R. Sabri M.H.M. Alammari A. Al-Kahtani A.A.N. Lu G. Kawasaki Z. Cooray V. Microwave radiation associated with positive narrow bipolar events |
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In this paper, we examined seven isolated positive Narrow Bipolar Events (NBEs), one positive NBE that initiated an IC flash progressed to a single-stroke Cloud-to-Ground (CG) flash, and one positive NBE that initiated an IC flash. Seven NBEs have been accompanied by significant Very-High Frequency (VHF) and microwave radiation pulses. We recorded all NBEs from two measurement stations (ST1 and ST2) separated at 13.3 km apart which consisted of fast antenna (FA) and slow antenna (SA) sensors, a magnetic field (B-field) sensor, a VHF sensor (60 MHz), and a microwave sensor (0.97 GHz). The waveforms were sampled at 2.5 GHz (400 ps). The key finding is that all microwave radiation pulses have been found to precede both the VHF radiation pulses and NBEs with average lead time of 63 � 39 ns and 122 � 143 ns, respectively. In comparison to stepped leader pulses or SLPs (conventional breakdown), the average lead time of microwave to VHF for NBEs (fast breakdown) was 88% faster compared to the average lead time of microwave to VHF for SLPs. Moreover, the average lead time of VHF to NBEs was 56% faster when compared to the average lead time of VHF to SLPs. The VHF interferometer map for an isolated NBE (NBE6) showed upward propagation of VHF radiation sources (fast negative breakdown) with initiation altitude, total length of the VHF radiation sources propagation, and estimated velocity were 10.2 � 0.3 km, 2.9 � 0.6 km, and 1.8 � 108 and 2.8 � 108 ms?1, respectively. On the other hand, interferometer map for an NBE that initiated a single-stroke CG (NBE3) showed bidirectional fast streamers propagation with initiation altitude, total length of the VHF radiation sources propagation, and estimated velocity were 14.0 � 0.4 km, 2.9 � 0.82 km, and 1.6 � 108 and 2.8 � 108 ms?1, respectively. Clearly, the microwave and VHF radiation pulses associated with positive NBEs have been emitted by different processes of fast breakdown mechanism. Therefore, it can be suggested that the microwave radiation is emitted by electron avalanches/corona while the VHF radiation is emitted by fast propagating streamers. � 2022 Elsevier Ltd |
| author2 |
57206727343 |
| author_facet |
57206727343 Baharin S.A.S. Ahmad M.R. Sabri M.H.M. Alammari A. Al-Kahtani A.A.N. Lu G. Kawasaki Z. Cooray V. |
| format |
Article |
| author |
Baharin S.A.S. Ahmad M.R. Sabri M.H.M. Alammari A. Al-Kahtani A.A.N. Lu G. Kawasaki Z. Cooray V. |
| author_sort |
Baharin S.A.S. |
| title |
Microwave radiation associated with positive narrow bipolar events |
| title_short |
Microwave radiation associated with positive narrow bipolar events |
| title_full |
Microwave radiation associated with positive narrow bipolar events |
| title_fullStr |
Microwave radiation associated with positive narrow bipolar events |
| title_full_unstemmed |
Microwave radiation associated with positive narrow bipolar events |
| title_sort |
microwave radiation associated with positive narrow bipolar events |
| publisher |
Elsevier Ltd |
| publishDate |
2024 |
| _version_ |
1814061067530141696 |
| score |
13.211869 |