Author-submitted data information
| ID | 506 |
| Title | Ionization Activity Detected During Dark Periods in Long Air Positive Sparks |
| Creator | Xiangen Zhao |
| Subject | Long air gap discharge data |
| Publisher | Xiukuan Zhao |
| Description | Experiments were carried out at the high-voltage laboratory of Huazhong University of Science & Technology, Wuhan, China. Positive long sparks were produced in a 1.4-m air gap under the positive switching impulse (200/5000 us), and the voltage waveform. Low-current measurements, Schlieren and standard photography as well as UV-photon detection was used to observe the electrical-optical-thermal characteristics of the dark period. The knowledge of the physical mechanisms of long positive sparks is necessary to solve engineering problems and to understand natural lightning. In these discharge phenomena, dark periods are prevalent, which refers to the time durations without ionization activity between the consecutive and separate streamer bursts. As the name implies, it is traditionally believed that ionization and luminosity are absent during dark periods. Recently, faint visible light was detected in dark periods, challenging the conventional perceptions. To this end, experiments were carried out to observe the electrical-optical-thermal properties of dark periods. The data used in the paper is provided here, and its details is introduced below. The data were obtained on Jul 25, 2021, in which the applied voltage (unit: kV), discharge current (unit: A), direct images and Schlieren images are included. Direct images are captured with a Phantom V1212 high-speed camera (HSC2) and a Nikon 50 mm F1.4 fixed lens, and the camera operated at a speed of 192,307 fps with an exposure time of 3.56 us. Schlieren images are recorded with Photron SA-X2 high-speed camera operating at the same settings as the Phantom camera. The testing conditions were temperature of 303 K, absolute humidity of 16.7 g/m3 and atmospheric pressure. The data were obtained on Apr 17, 2022, in which the applied voltage (unit: kV), discharge current (unit: A), direct images and the time-resolved UV irradiance (330 - 340 nm) are included. Direct images are captured with a Phantom V1212 high-speed camera (HSC2) and a Nikon 50 mm F1.4 fixed lens, and the camera operated at a speed of 192,307 fps with an exposure time of 3.56 us. The long-wave ultraviolet (UV) optical emission (337 nm) was observed by a multianode photomultiplier tube assembly (Hamamatsu, H10515B-103) with a narrow-band-pass filter (in the range between 330 and 340 nm). The testing conditions were temperature of 291 K, absolute humidity of 9.2 g/m3 and atmospheric pressure. |
| Contributor | Marley Becerra, Xiankang Wang, Yang Liu, Yaping Du, and Junjia He |
| Date | Jul 25, 2021；Apr 17, 2022 |
| Type | |
| Format | The voltage, current and UV waveform is in origin .opj format, and all images are in .tif format. |
| URL | http://www.geophys.ac.cn/ArticleData/20230406SparksData.zip |
| DOI | 10.12197/2023GA007 |
| Source | |
| Language | eng |
| Relation | |
| Coverage | |
| Rights | Huazhong University of Science & Technology; The Hong Kong Polytechnic University |