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Takehiko Sato - One of the best experts on this subject based on the ideXlab platform.
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initiation process and Propagation Mechanism of positive streamer discharge in water
Journal of Applied Physics, 2014Co-Authors: Hidemasa Fujita, Seiji Kanazawa, Kiyonobu Ohtani, Atsuki Komiya, Toshiro Kaneko, Takehiko SatoAbstract:The aim of this study was to clarify the initiation process and the Propagation Mechanism of positive underwater streamers under the application of pulsed voltage with a duration of 10 μs, focusing on two different theories of electrical discharges in liquids: the bubble theory and the direct ionization theory. The initiation process, which is the time lag from the beginning of voltage application to streamer inception, was found to be related to the bubble theory. In this process, Joule heating resulted in the formation of a bubble cluster at the tip of a needle electrode. Streamer inception was observed from the tip of a protrusion on the surface of this bubble cluster, which acted as a virtual sharp electrode to enhance the local electric field to a level greater than 10 MV/cm. Streak imaging of secondary streamer Propagation showed that luminescence preceded gas channel generation, suggesting a Mechanism of direct ionization in water. Streak imaging of primary streamer Propagation revealed intermittent Propagation, synchronized with repetitive pulsed currents. Shadowgraph imaging of streamers synchronized with the light emission signal indicated the possibility of direct ionization in water for primary streamer Propagation as well as for secondary streamer Propagation.
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Spatiotemporal analysis of Propagation Mechanism of positive primary streamer in water
Journal of Applied Physics, 2013Co-Authors: Hidemasa Fujita, Seiji Kanazawa, Kiyonobu Ohtani, Atsuki Komiya, Takehiko SatoAbstract:Currently, further clarification of pre-breakdown phenomena in water such as Propagation Mechanisms of primary and secondary streamers are needed because applications of aqueous plasma to environmental and medical treatments are increasing. In this study, a series of primary streamer Propagations in ultrapure water was visualized at 100-Mega frames per second (100 Mfps) in the range of 400 μm square using an ultra high-speed camera with a microscope lens when a single-shot pulsed positive voltage was applied to a needle electrode placed in a quartz cell. Every observation was synchronized with the waveforms of the applied voltage and the discharge current. The primary streamer, having many filamentary channels, started to propagate semi-spherically with a velocity of about 2 km/s when the pulsed currents occurred. Although most filamentary channels disappeared 400 ns after the beginning of the primary streamer, a few of them continued propagating with almost the same velocity (about 2 km/s) as long as the...
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spatiotemporal analysis of Propagation Mechanism of positive primary streamer in water
Journal of Applied Physics, 2013Co-Authors: Hidemasa Fujita, Seiji Kanazawa, Kiyonobu Ohtani, Atsuki Komiya, Takehiko SatoAbstract:Currently, further clarification of pre-breakdown phenomena in water such as Propagation Mechanisms of primary and secondary streamers are needed because applications of aqueous plasma to environmental and medical treatments are increasing. In this study, a series of primary streamer Propagations in ultrapure water was visualized at 100-Mega frames per second (100 Mfps) in the range of 400 μm square using an ultra high-speed camera with a microscope lens when a single-shot pulsed positive voltage was applied to a needle electrode placed in a quartz cell. Every observation was synchronized with the waveforms of the applied voltage and the discharge current. The primary streamer, having many filamentary channels, started to propagate semi-spherically with a velocity of about 2 km/s when the pulsed currents occurred. Although most filamentary channels disappeared 400 ns after the beginning of the primary streamer, a few of them continued propagating with almost the same velocity (about 2 km/s) as long as the repetitive pulsed currents flowed. Shock waves were iteratively generated and streamer channels were formed while the repetitive pulsed currents were flowing. Thus, we concluded that the positive primary streamer in water propagates progressively with each repetitive pulsed current.
Hidemasa Fujita - One of the best experts on this subject based on the ideXlab platform.
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initiation process and Propagation Mechanism of positive streamer discharge in water
Journal of Applied Physics, 2014Co-Authors: Hidemasa Fujita, Seiji Kanazawa, Kiyonobu Ohtani, Atsuki Komiya, Toshiro Kaneko, Takehiko SatoAbstract:The aim of this study was to clarify the initiation process and the Propagation Mechanism of positive underwater streamers under the application of pulsed voltage with a duration of 10 μs, focusing on two different theories of electrical discharges in liquids: the bubble theory and the direct ionization theory. The initiation process, which is the time lag from the beginning of voltage application to streamer inception, was found to be related to the bubble theory. In this process, Joule heating resulted in the formation of a bubble cluster at the tip of a needle electrode. Streamer inception was observed from the tip of a protrusion on the surface of this bubble cluster, which acted as a virtual sharp electrode to enhance the local electric field to a level greater than 10 MV/cm. Streak imaging of secondary streamer Propagation showed that luminescence preceded gas channel generation, suggesting a Mechanism of direct ionization in water. Streak imaging of primary streamer Propagation revealed intermittent Propagation, synchronized with repetitive pulsed currents. Shadowgraph imaging of streamers synchronized with the light emission signal indicated the possibility of direct ionization in water for primary streamer Propagation as well as for secondary streamer Propagation.
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Spatiotemporal analysis of Propagation Mechanism of positive primary streamer in water
Journal of Applied Physics, 2013Co-Authors: Hidemasa Fujita, Seiji Kanazawa, Kiyonobu Ohtani, Atsuki Komiya, Takehiko SatoAbstract:Currently, further clarification of pre-breakdown phenomena in water such as Propagation Mechanisms of primary and secondary streamers are needed because applications of aqueous plasma to environmental and medical treatments are increasing. In this study, a series of primary streamer Propagations in ultrapure water was visualized at 100-Mega frames per second (100 Mfps) in the range of 400 μm square using an ultra high-speed camera with a microscope lens when a single-shot pulsed positive voltage was applied to a needle electrode placed in a quartz cell. Every observation was synchronized with the waveforms of the applied voltage and the discharge current. The primary streamer, having many filamentary channels, started to propagate semi-spherically with a velocity of about 2 km/s when the pulsed currents occurred. Although most filamentary channels disappeared 400 ns after the beginning of the primary streamer, a few of them continued propagating with almost the same velocity (about 2 km/s) as long as the...
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spatiotemporal analysis of Propagation Mechanism of positive primary streamer in water
Journal of Applied Physics, 2013Co-Authors: Hidemasa Fujita, Seiji Kanazawa, Kiyonobu Ohtani, Atsuki Komiya, Takehiko SatoAbstract:Currently, further clarification of pre-breakdown phenomena in water such as Propagation Mechanisms of primary and secondary streamers are needed because applications of aqueous plasma to environmental and medical treatments are increasing. In this study, a series of primary streamer Propagations in ultrapure water was visualized at 100-Mega frames per second (100 Mfps) in the range of 400 μm square using an ultra high-speed camera with a microscope lens when a single-shot pulsed positive voltage was applied to a needle electrode placed in a quartz cell. Every observation was synchronized with the waveforms of the applied voltage and the discharge current. The primary streamer, having many filamentary channels, started to propagate semi-spherically with a velocity of about 2 km/s when the pulsed currents occurred. Although most filamentary channels disappeared 400 ns after the beginning of the primary streamer, a few of them continued propagating with almost the same velocity (about 2 km/s) as long as the repetitive pulsed currents flowed. Shock waves were iteratively generated and streamer channels were formed while the repetitive pulsed currents were flowing. Thus, we concluded that the positive primary streamer in water propagates progressively with each repetitive pulsed current.
Atsuki Komiya - One of the best experts on this subject based on the ideXlab platform.
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initiation process and Propagation Mechanism of positive streamer discharge in water
Journal of Applied Physics, 2014Co-Authors: Hidemasa Fujita, Seiji Kanazawa, Kiyonobu Ohtani, Atsuki Komiya, Toshiro Kaneko, Takehiko SatoAbstract:The aim of this study was to clarify the initiation process and the Propagation Mechanism of positive underwater streamers under the application of pulsed voltage with a duration of 10 μs, focusing on two different theories of electrical discharges in liquids: the bubble theory and the direct ionization theory. The initiation process, which is the time lag from the beginning of voltage application to streamer inception, was found to be related to the bubble theory. In this process, Joule heating resulted in the formation of a bubble cluster at the tip of a needle electrode. Streamer inception was observed from the tip of a protrusion on the surface of this bubble cluster, which acted as a virtual sharp electrode to enhance the local electric field to a level greater than 10 MV/cm. Streak imaging of secondary streamer Propagation showed that luminescence preceded gas channel generation, suggesting a Mechanism of direct ionization in water. Streak imaging of primary streamer Propagation revealed intermittent Propagation, synchronized with repetitive pulsed currents. Shadowgraph imaging of streamers synchronized with the light emission signal indicated the possibility of direct ionization in water for primary streamer Propagation as well as for secondary streamer Propagation.
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Spatiotemporal analysis of Propagation Mechanism of positive primary streamer in water
Journal of Applied Physics, 2013Co-Authors: Hidemasa Fujita, Seiji Kanazawa, Kiyonobu Ohtani, Atsuki Komiya, Takehiko SatoAbstract:Currently, further clarification of pre-breakdown phenomena in water such as Propagation Mechanisms of primary and secondary streamers are needed because applications of aqueous plasma to environmental and medical treatments are increasing. In this study, a series of primary streamer Propagations in ultrapure water was visualized at 100-Mega frames per second (100 Mfps) in the range of 400 μm square using an ultra high-speed camera with a microscope lens when a single-shot pulsed positive voltage was applied to a needle electrode placed in a quartz cell. Every observation was synchronized with the waveforms of the applied voltage and the discharge current. The primary streamer, having many filamentary channels, started to propagate semi-spherically with a velocity of about 2 km/s when the pulsed currents occurred. Although most filamentary channels disappeared 400 ns after the beginning of the primary streamer, a few of them continued propagating with almost the same velocity (about 2 km/s) as long as the...
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spatiotemporal analysis of Propagation Mechanism of positive primary streamer in water
Journal of Applied Physics, 2013Co-Authors: Hidemasa Fujita, Seiji Kanazawa, Kiyonobu Ohtani, Atsuki Komiya, Takehiko SatoAbstract:Currently, further clarification of pre-breakdown phenomena in water such as Propagation Mechanisms of primary and secondary streamers are needed because applications of aqueous plasma to environmental and medical treatments are increasing. In this study, a series of primary streamer Propagations in ultrapure water was visualized at 100-Mega frames per second (100 Mfps) in the range of 400 μm square using an ultra high-speed camera with a microscope lens when a single-shot pulsed positive voltage was applied to a needle electrode placed in a quartz cell. Every observation was synchronized with the waveforms of the applied voltage and the discharge current. The primary streamer, having many filamentary channels, started to propagate semi-spherically with a velocity of about 2 km/s when the pulsed currents occurred. Although most filamentary channels disappeared 400 ns after the beginning of the primary streamer, a few of them continued propagating with almost the same velocity (about 2 km/s) as long as the repetitive pulsed currents flowed. Shock waves were iteratively generated and streamer channels were formed while the repetitive pulsed currents were flowing. Thus, we concluded that the positive primary streamer in water propagates progressively with each repetitive pulsed current.
Kiyonobu Ohtani - One of the best experts on this subject based on the ideXlab platform.
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initiation process and Propagation Mechanism of positive streamer discharge in water
Journal of Applied Physics, 2014Co-Authors: Hidemasa Fujita, Seiji Kanazawa, Kiyonobu Ohtani, Atsuki Komiya, Toshiro Kaneko, Takehiko SatoAbstract:The aim of this study was to clarify the initiation process and the Propagation Mechanism of positive underwater streamers under the application of pulsed voltage with a duration of 10 μs, focusing on two different theories of electrical discharges in liquids: the bubble theory and the direct ionization theory. The initiation process, which is the time lag from the beginning of voltage application to streamer inception, was found to be related to the bubble theory. In this process, Joule heating resulted in the formation of a bubble cluster at the tip of a needle electrode. Streamer inception was observed from the tip of a protrusion on the surface of this bubble cluster, which acted as a virtual sharp electrode to enhance the local electric field to a level greater than 10 MV/cm. Streak imaging of secondary streamer Propagation showed that luminescence preceded gas channel generation, suggesting a Mechanism of direct ionization in water. Streak imaging of primary streamer Propagation revealed intermittent Propagation, synchronized with repetitive pulsed currents. Shadowgraph imaging of streamers synchronized with the light emission signal indicated the possibility of direct ionization in water for primary streamer Propagation as well as for secondary streamer Propagation.
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Spatiotemporal analysis of Propagation Mechanism of positive primary streamer in water
Journal of Applied Physics, 2013Co-Authors: Hidemasa Fujita, Seiji Kanazawa, Kiyonobu Ohtani, Atsuki Komiya, Takehiko SatoAbstract:Currently, further clarification of pre-breakdown phenomena in water such as Propagation Mechanisms of primary and secondary streamers are needed because applications of aqueous plasma to environmental and medical treatments are increasing. In this study, a series of primary streamer Propagations in ultrapure water was visualized at 100-Mega frames per second (100 Mfps) in the range of 400 μm square using an ultra high-speed camera with a microscope lens when a single-shot pulsed positive voltage was applied to a needle electrode placed in a quartz cell. Every observation was synchronized with the waveforms of the applied voltage and the discharge current. The primary streamer, having many filamentary channels, started to propagate semi-spherically with a velocity of about 2 km/s when the pulsed currents occurred. Although most filamentary channels disappeared 400 ns after the beginning of the primary streamer, a few of them continued propagating with almost the same velocity (about 2 km/s) as long as the...
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spatiotemporal analysis of Propagation Mechanism of positive primary streamer in water
Journal of Applied Physics, 2013Co-Authors: Hidemasa Fujita, Seiji Kanazawa, Kiyonobu Ohtani, Atsuki Komiya, Takehiko SatoAbstract:Currently, further clarification of pre-breakdown phenomena in water such as Propagation Mechanisms of primary and secondary streamers are needed because applications of aqueous plasma to environmental and medical treatments are increasing. In this study, a series of primary streamer Propagations in ultrapure water was visualized at 100-Mega frames per second (100 Mfps) in the range of 400 μm square using an ultra high-speed camera with a microscope lens when a single-shot pulsed positive voltage was applied to a needle electrode placed in a quartz cell. Every observation was synchronized with the waveforms of the applied voltage and the discharge current. The primary streamer, having many filamentary channels, started to propagate semi-spherically with a velocity of about 2 km/s when the pulsed currents occurred. Although most filamentary channels disappeared 400 ns after the beginning of the primary streamer, a few of them continued propagating with almost the same velocity (about 2 km/s) as long as the repetitive pulsed currents flowed. Shock waves were iteratively generated and streamer channels were formed while the repetitive pulsed currents were flowing. Thus, we concluded that the positive primary streamer in water propagates progressively with each repetitive pulsed current.
Seiji Kanazawa - One of the best experts on this subject based on the ideXlab platform.
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initiation process and Propagation Mechanism of positive streamer discharge in water
Journal of Applied Physics, 2014Co-Authors: Hidemasa Fujita, Seiji Kanazawa, Kiyonobu Ohtani, Atsuki Komiya, Toshiro Kaneko, Takehiko SatoAbstract:The aim of this study was to clarify the initiation process and the Propagation Mechanism of positive underwater streamers under the application of pulsed voltage with a duration of 10 μs, focusing on two different theories of electrical discharges in liquids: the bubble theory and the direct ionization theory. The initiation process, which is the time lag from the beginning of voltage application to streamer inception, was found to be related to the bubble theory. In this process, Joule heating resulted in the formation of a bubble cluster at the tip of a needle electrode. Streamer inception was observed from the tip of a protrusion on the surface of this bubble cluster, which acted as a virtual sharp electrode to enhance the local electric field to a level greater than 10 MV/cm. Streak imaging of secondary streamer Propagation showed that luminescence preceded gas channel generation, suggesting a Mechanism of direct ionization in water. Streak imaging of primary streamer Propagation revealed intermittent Propagation, synchronized with repetitive pulsed currents. Shadowgraph imaging of streamers synchronized with the light emission signal indicated the possibility of direct ionization in water for primary streamer Propagation as well as for secondary streamer Propagation.
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Spatiotemporal analysis of Propagation Mechanism of positive primary streamer in water
Journal of Applied Physics, 2013Co-Authors: Hidemasa Fujita, Seiji Kanazawa, Kiyonobu Ohtani, Atsuki Komiya, Takehiko SatoAbstract:Currently, further clarification of pre-breakdown phenomena in water such as Propagation Mechanisms of primary and secondary streamers are needed because applications of aqueous plasma to environmental and medical treatments are increasing. In this study, a series of primary streamer Propagations in ultrapure water was visualized at 100-Mega frames per second (100 Mfps) in the range of 400 μm square using an ultra high-speed camera with a microscope lens when a single-shot pulsed positive voltage was applied to a needle electrode placed in a quartz cell. Every observation was synchronized with the waveforms of the applied voltage and the discharge current. The primary streamer, having many filamentary channels, started to propagate semi-spherically with a velocity of about 2 km/s when the pulsed currents occurred. Although most filamentary channels disappeared 400 ns after the beginning of the primary streamer, a few of them continued propagating with almost the same velocity (about 2 km/s) as long as the...
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spatiotemporal analysis of Propagation Mechanism of positive primary streamer in water
Journal of Applied Physics, 2013Co-Authors: Hidemasa Fujita, Seiji Kanazawa, Kiyonobu Ohtani, Atsuki Komiya, Takehiko SatoAbstract:Currently, further clarification of pre-breakdown phenomena in water such as Propagation Mechanisms of primary and secondary streamers are needed because applications of aqueous plasma to environmental and medical treatments are increasing. In this study, a series of primary streamer Propagations in ultrapure water was visualized at 100-Mega frames per second (100 Mfps) in the range of 400 μm square using an ultra high-speed camera with a microscope lens when a single-shot pulsed positive voltage was applied to a needle electrode placed in a quartz cell. Every observation was synchronized with the waveforms of the applied voltage and the discharge current. The primary streamer, having many filamentary channels, started to propagate semi-spherically with a velocity of about 2 km/s when the pulsed currents occurred. Although most filamentary channels disappeared 400 ns after the beginning of the primary streamer, a few of them continued propagating with almost the same velocity (about 2 km/s) as long as the repetitive pulsed currents flowed. Shock waves were iteratively generated and streamer channels were formed while the repetitive pulsed currents were flowing. Thus, we concluded that the positive primary streamer in water propagates progressively with each repetitive pulsed current.
