Pub Date : 2024-12-03DOI: 10.1109/TPS.2024.3501310
Chun-Sung Jao;Wojciech J. Miloch;Yohei Miyake
The multineedle Langmuir probe (m-NLP) instrument, consisting of two or more fixed-bias cylindrical Langmuir probes, is designed to enhance data resolution, particularly for in situ measurement in space missions. However, like other spacecraft and instruments used in space missions, these probes may interact with the surrounding plasma, potentially leading to errors in plasma measurements. In this article, we investigate the interaction between a double Langmuir probe setup and plasma flow, specifically focusing on how the collected current on the probes is affected by the electric bias and varying distances between the probes. Results from Particle-in-Cell (PIC) simulations show that with a front probe and a rear probe aligned along the plasma flow, not only may the rear probe’s collected current be affected, but the entire system may also experience significant influences if the distance between probes is short. In particular, if both probes are positively biased, as in the m-NLP instrument, they will not significantly influence each other’s measurements if the distance between them is longer than 30 Debye lengths. We also employ test particle simulations to further illustrate the interaction between the double Langmuir probe system and its surrounding plasma.
{"title":"Collected Current by a Double Langmuir Probe Setup With Plasma Flow","authors":"Chun-Sung Jao;Wojciech J. Miloch;Yohei Miyake","doi":"10.1109/TPS.2024.3501310","DOIUrl":"https://doi.org/10.1109/TPS.2024.3501310","url":null,"abstract":"The multineedle Langmuir probe (m-NLP) instrument, consisting of two or more fixed-bias cylindrical Langmuir probes, is designed to enhance data resolution, particularly for in situ measurement in space missions. However, like other spacecraft and instruments used in space missions, these probes may interact with the surrounding plasma, potentially leading to errors in plasma measurements. In this article, we investigate the interaction between a double Langmuir probe setup and plasma flow, specifically focusing on how the collected current on the probes is affected by the electric bias and varying distances between the probes. Results from Particle-in-Cell (PIC) simulations show that with a front probe and a rear probe aligned along the plasma flow, not only may the rear probe’s collected current be affected, but the entire system may also experience significant influences if the distance between probes is short. In particular, if both probes are positively biased, as in the m-NLP instrument, they will not significantly influence each other’s measurements if the distance between them is longer than 30 Debye lengths. We also employ test particle simulations to further illustrate the interaction between the double Langmuir probe system and its surrounding plasma.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 10","pages":"5222-5233"},"PeriodicalIF":1.3,"publicationDate":"2024-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10776030","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142890225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-27DOI: 10.1109/TPS.2024.3499932
Pengcheng Yu;Yu Liu;Xiangqun Liu;Jiuhou Lei
It is difficult to diagnose the electron density of a high-temperature ablation plasma flow field because a traditional cylindrical Langmuir probe (CP) is easily damaged under these conditions. In this work, a new type of embedded Langmuir probe, referred to as a double flush-mounted probe (DFP), was developed to measure the electron density of a high-temperature ablation plasma flow field. It was verified that the DFP can work stably in different types of wind tunnels. In addition, the results from the new probe were compared with those from a CP. The results suggest that the DFP can be used to accurately determine the plasma density over long time periods. Therefore, this work provides a feasible method for solving the problem of online diagnostics in a high-temperature ablation plasma flow field.
{"title":"Measurement of the Electron Density of a Wind-Tunnel Plasma Using a Double Flush-Mounted Probe","authors":"Pengcheng Yu;Yu Liu;Xiangqun Liu;Jiuhou Lei","doi":"10.1109/TPS.2024.3499932","DOIUrl":"https://doi.org/10.1109/TPS.2024.3499932","url":null,"abstract":"It is difficult to diagnose the electron density of a high-temperature ablation plasma flow field because a traditional cylindrical Langmuir probe (CP) is easily damaged under these conditions. In this work, a new type of embedded Langmuir probe, referred to as a double flush-mounted probe (DFP), was developed to measure the electron density of a high-temperature ablation plasma flow field. It was verified that the DFP can work stably in different types of wind tunnels. In addition, the results from the new probe were compared with those from a CP. The results suggest that the DFP can be used to accurately determine the plasma density over long time periods. Therefore, this work provides a feasible method for solving the problem of online diagnostics in a high-temperature ablation plasma flow field.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 10","pages":"5234-5240"},"PeriodicalIF":1.3,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142890227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-26DOI: 10.1109/TPS.2024.3496499
Xiaoqian Zhang;Haojie Cao;Li Chen;Sitong Tian
Reducing breakdown delay and jitter, and broadening the working voltage range of gas switches have been paramount challenges in pulse switch research. This study centers on trigger methods of trigatron gas switch, designing and testing three trigger structures—conventional, microprotrusion, and microplasma jet—under various conditions. Furthermore, synchronization experiments were conducted and compared under different trigger structures. The experimental results showed that the trigatron switch exhibits fast and slow breakdown modes with the conventional trigger structure and both the microprotrusion and microplasma jet trigger structures can reduce the breakdown delay and jitter by creating strong electric field distortion and providing initial electrons. The microprotrusion structure enables the switch to operate stably at a working coefficient higher than 50%, with a breakdown delay and jitter as low as 76.44 and 1.37 ns, while the microplasma jet structure enables the switch to operate at a working coefficient as low as 40%, with a breakdown delay and jitter of 78.15 and 5.83 ns, respectively. Compared with the microprotrusion structure, the microplasma jet trigger structure can achieve a lower working coefficient and performs excellently in synchronization experiments.
{"title":"Exploring Wide Working Coefficient of Trigatron Gas Switches: A Comparative Study With Different Trigger Structures","authors":"Xiaoqian Zhang;Haojie Cao;Li Chen;Sitong Tian","doi":"10.1109/TPS.2024.3496499","DOIUrl":"https://doi.org/10.1109/TPS.2024.3496499","url":null,"abstract":"Reducing breakdown delay and jitter, and broadening the working voltage range of gas switches have been paramount challenges in pulse switch research. This study centers on trigger methods of trigatron gas switch, designing and testing three trigger structures—conventional, microprotrusion, and microplasma jet—under various conditions. Furthermore, synchronization experiments were conducted and compared under different trigger structures. The experimental results showed that the trigatron switch exhibits fast and slow breakdown modes with the conventional trigger structure and both the microprotrusion and microplasma jet trigger structures can reduce the breakdown delay and jitter by creating strong electric field distortion and providing initial electrons. The microprotrusion structure enables the switch to operate stably at a working coefficient higher than 50%, with a breakdown delay and jitter as low as 76.44 and 1.37 ns, while the microplasma jet structure enables the switch to operate at a working coefficient as low as 40%, with a breakdown delay and jitter of 78.15 and 5.83 ns, respectively. Compared with the microprotrusion structure, the microplasma jet trigger structure can achieve a lower working coefficient and performs excellently in synchronization experiments.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 10","pages":"5256-5265"},"PeriodicalIF":1.3,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142890222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-26DOI: 10.1109/TPS.2024.3501679
Andrey D. Andreev
Presents corrections to the paper, (Errata to “Particle-in-Cell (PIC) Simulations of A6 “Classic” “1.58/2.11/4.11” Geometry Relativistic or High-Voltage Magnetron With Radial Output of Microwave Power: A Historical Overview From Personal Experience”).
{"title":"Errata to “Particle-in-Cell (PIC) Simulations of A6 “Classic” “1.58/2.11/4.11” Geometry Relativistic or High-Voltage Magnetron With Radial Output of Microwave Power: A Historical Overview From Personal Experience”","authors":"Andrey D. Andreev","doi":"10.1109/TPS.2024.3501679","DOIUrl":"https://doi.org/10.1109/TPS.2024.3501679","url":null,"abstract":"Presents corrections to the paper, (Errata to “Particle-in-Cell (PIC) Simulations of A6 “Classic” “1.58/2.11/4.11” Geometry Relativistic or High-Voltage Magnetron With Radial Output of Microwave Power: A Historical Overview From Personal Experience”).","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 10","pages":"5303-5303"},"PeriodicalIF":1.3,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142890246","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Atmospheric pressure plasma (APP) treatment improves seed germination by introducing functional groups or etching to change its surface chemical characteristics. This study focuses on improving rice surface properties and reveals that water acting as a buffer plays a key role in APP treatment for the enhancement of seed germination. After a 150-s water buffer APP treatment, the germination percentage of rice seeds increased from 45% to 84% compared with the control group. This improvement can be attributed to the enrichment of surface polar functional groups resulting from the plasma treatment. Surface energy calculations revealed a remarkable increase in the polar component, leading to a substantial reduction in the water contact angle (WCA) from 105° to 40°. This indicates a significant enhancement in surface wettability, rendering it more hydrophilic. Consequently, water uptake from the seed surface also significantly increased. Moreover, X-ray photoelectron spectroscopy (XPS) showed that polar −NO functional groups were enhanced on the seed surface treated by APP with water buffer. The −NO functional groups were formed through a surface reaction between oxygen-excited species OH $^{ast }$ and N $_{2}^{+}$ ions or N $_{2}^{ast }$ species on the seed surface, which can improve the wettability and provide additional nutrition to seed germination. Consequently, APP seed treatment with water buffer can potentially facilitate seed germination.
{"title":"Rice Seed Germination Improvement by Atmospheric Pressure Plasma Surface Modification With Water Buffer","authors":"Pin-Yuan Lai;Yuan-Tai Lai;Sheng-Yu Hsu;Po-Yu Chen;Jenq-Gong Duh","doi":"10.1109/TPS.2024.3497133","DOIUrl":"https://doi.org/10.1109/TPS.2024.3497133","url":null,"abstract":"Atmospheric pressure plasma (APP) treatment improves seed germination by introducing functional groups or etching to change its surface chemical characteristics. This study focuses on improving rice surface properties and reveals that water acting as a buffer plays a key role in APP treatment for the enhancement of seed germination. After a 150-s water buffer APP treatment, the germination percentage of rice seeds increased from 45% to 84% compared with the control group. This improvement can be attributed to the enrichment of surface polar functional groups resulting from the plasma treatment. Surface energy calculations revealed a remarkable increase in the polar component, leading to a substantial reduction in the water contact angle (WCA) from 105° to 40°. This indicates a significant enhancement in surface wettability, rendering it more hydrophilic. Consequently, water uptake from the seed surface also significantly increased. Moreover, X-ray photoelectron spectroscopy (XPS) showed that polar −NO functional groups were enhanced on the seed surface treated by APP with water buffer. The −NO functional groups were formed through a surface reaction between oxygen-excited species OH\u0000<inline-formula> <tex-math>$^{ast }$ </tex-math></inline-formula>\u0000 and N\u0000<inline-formula> <tex-math>$_{2}^{+}$ </tex-math></inline-formula>\u0000 ions or N\u0000<inline-formula> <tex-math>$_{2}^{ast }$ </tex-math></inline-formula>\u0000 species on the seed surface, which can improve the wettability and provide additional nutrition to seed germination. Consequently, APP seed treatment with water buffer can potentially facilitate seed germination.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 10","pages":"5184-5192"},"PeriodicalIF":1.3,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142890138","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-25DOI: 10.1109/TPS.2024.3492816
Adam M. Aaron;G. Ted Boyd;Aravind Shanmugasundaram;Vivek Rao;Jonathan Perry;David Irick;Theodore M. Biewer;M. Aftab Hussain
The Material Plasma Exposure eXperiment (MPEX) is a steady-state linear plasma device designed to expose neutron-irradiated materials to fusion divertor prototypic plasma conditions to perform plasma-material interaction (PMI) studies. The MPEX device will be capable of ion fluxes of 1025 m−2s−1, power fluxes up to 40 MW/m2, ion fluences up to 1031 m−2, and operation at steady state for up to 106 s with magnetic fields up to 2.5 T. PMIs occur when the plasma directly impinges upon a surface. In the case of MPEX, this occurs primarily at the MPEX target. Observation of interaction using a variety of instruments is required. A PMI chamber was designed to enable these observations using currently envisioned diagnostics and to accommodate future instruments. The design includes 59 plasma-facing ports, 10 of which explicitly point at the target, and an additional 10 ports that can be used to assess the vacuum space in the chamber. The entire vacuum chamber is water-cooled and will experience sustained heat from plasma radiated power, microwaves, and neutral gas thermal loads. Because of the method of fabrication, this chamber has undergone significant manufacturability testing. The chamber includes provisions for chamber, plasma, and target diagnostics such as a residual gas analyzer, Thomson scattering lasers, and both visible and IR cameras. The design effort included operational testing of the autocoupler to ensure vacuum integrity and included machining and welding studies to verify that the tolerances required by the diagnostics could be held. Provisions have also been included to eventually accommodate a water-cooled target dump, an irradiated sample recovery module, and any other hardware needed to support future target designs and diagnostics.
{"title":"The Final Design of the Plasma–Material Interaction Chamber for the Material Plasma Exposure eXperiment","authors":"Adam M. Aaron;G. Ted Boyd;Aravind Shanmugasundaram;Vivek Rao;Jonathan Perry;David Irick;Theodore M. Biewer;M. Aftab Hussain","doi":"10.1109/TPS.2024.3492816","DOIUrl":"https://doi.org/10.1109/TPS.2024.3492816","url":null,"abstract":"The Material Plasma Exposure eXperiment (MPEX) is a steady-state linear plasma device designed to expose neutron-irradiated materials to fusion divertor prototypic plasma conditions to perform plasma-material interaction (PMI) studies. The MPEX device will be capable of ion fluxes of 1025 m−2s−1, power fluxes up to 40 MW/m2, ion fluences up to 1031 m−2, and operation at steady state for up to 106 s with magnetic fields up to 2.5 T. PMIs occur when the plasma directly impinges upon a surface. In the case of MPEX, this occurs primarily at the MPEX target. Observation of interaction using a variety of instruments is required. A PMI chamber was designed to enable these observations using currently envisioned diagnostics and to accommodate future instruments. The design includes 59 plasma-facing ports, 10 of which explicitly point at the target, and an additional 10 ports that can be used to assess the vacuum space in the chamber. The entire vacuum chamber is water-cooled and will experience sustained heat from plasma radiated power, microwaves, and neutral gas thermal loads. Because of the method of fabrication, this chamber has undergone significant manufacturability testing. The chamber includes provisions for chamber, plasma, and target diagnostics such as a residual gas analyzer, Thomson scattering lasers, and both visible and IR cameras. The design effort included operational testing of the autocoupler to ensure vacuum integrity and included machining and welding studies to verify that the tolerances required by the diagnostics could be held. Provisions have also been included to eventually accommodate a water-cooled target dump, an irradiated sample recovery module, and any other hardware needed to support future target designs and diagnostics.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 9","pages":"4103-4107"},"PeriodicalIF":1.3,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142797988","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-21DOI: 10.1109/TPS.2024.3492696
Shawn Wenjie Tang;Walter Gekelman
This article details the construction of a retarding field energy analyzer (RFEA) designed to measure the ion energy distribution function (IEDF) in a moderately dense laboratory plasma, such as that produced in the Large Plasma Device (LAPD). The RFEA was specifically developed to study ion acceleration in a magnetic reconnection experiment involving two kink-unstable flux ropes. It features four independently biasable grids, an electrically and thermally insulating exterior, a mesh grid stack as the entrance grid to collect more current, a solder-less design for easy assembly, and is constructed with readily available off-the-shelf materials for quick turnaround time. In this experiment, the RFEA demonstrated continuous operation for several days under LAPD conditions. It measured low-energy thermal ions with energies below 20 eV and observed field-aligned ion beams with energies between 9 and 15 eV near the reconnection region between the two ropes. For brevity, a detailed analysis of the ion beam and supporting 3-D gyrokinetic simulations are presented in a related manuscript [Tang et al., Phys. Plasmas 30, 082104 (2023)]. Ion temperature measurements of thermal ions within the flux ropes from the RFEA were consistent with those inferred from the spectroscopy of Doppler-broadened helium II spectral lines (320.3 nm).
{"title":"Design of a Retarding Field Energy Analyzer for the Large Plasma Device","authors":"Shawn Wenjie Tang;Walter Gekelman","doi":"10.1109/TPS.2024.3492696","DOIUrl":"https://doi.org/10.1109/TPS.2024.3492696","url":null,"abstract":"This article details the construction of a retarding field energy analyzer (RFEA) designed to measure the ion energy distribution function (IEDF) in a moderately dense laboratory plasma, such as that produced in the Large Plasma Device (LAPD). The RFEA was specifically developed to study ion acceleration in a magnetic reconnection experiment involving two kink-unstable flux ropes. It features four independently biasable grids, an electrically and thermally insulating exterior, a mesh grid stack as the entrance grid to collect more current, a solder-less design for easy assembly, and is constructed with readily available off-the-shelf materials for quick turnaround time. In this experiment, the RFEA demonstrated continuous operation for several days under LAPD conditions. It measured low-energy thermal ions with energies below 20 eV and observed field-aligned ion beams with energies between 9 and 15 eV near the reconnection region between the two ropes. For brevity, a detailed analysis of the ion beam and supporting 3-D gyrokinetic simulations are presented in a related manuscript [Tang et al., Phys. Plasmas 30, 082104 (2023)]. Ion temperature measurements of thermal ions within the flux ropes from the RFEA were consistent with those inferred from the spectroscopy of Doppler-broadened helium II spectral lines (320.3 nm).","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 10","pages":"5205-5215"},"PeriodicalIF":1.3,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142890137","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Gyrotron traveling wave amplifiers (Gyro-TWA) have both the characteristics of high power and broadband, which have wide application prospects in many important military fields, such as millimeter wave detection, high-resolution imaging radar, electronic countermeasures, and so on. The gyro-TWA based on axis encircling electron beam can stably operate at high-order harmonic state, reducing the operating magnetic field linearly proportional with the harmonic number and even achieving superconducting free operation. It can improve the flexibility and maneuverability of gyro-TWA. In this article, a Ka-band second-harmonic gyro-TWA with an interaction circuit of helically corrugated waveguide (HCW) is designed. The simulation results indicate that the gyro-TWT driven by a 75-kV, 7-A axis-encircling electron beam can achieve about 160-kW maximum power with a saturation gain of 29 dB, an efficiency of 30.48%, and a bandwidth of 4 GHz from 27 to 31 GHz. Meanwhile, the design details of the circular polarizer and input coupler are reported.
{"title":"Simulation Design of a Ka-Band Helically Corrugated Waveguide Gyro-TWA Based on Axis-Encircling Electron Beam","authors":"Ruiqi Lu;Qiao Liu;Qixiang Zhao;Jialang Ling;Chaojun Lei;Dongshuo Gao;Xu Zeng;E’Feng Wang;Jinjun Feng","doi":"10.1109/TPS.2024.3495986","DOIUrl":"https://doi.org/10.1109/TPS.2024.3495986","url":null,"abstract":"Gyrotron traveling wave amplifiers (Gyro-TWA) have both the characteristics of high power and broadband, which have wide application prospects in many important military fields, such as millimeter wave detection, high-resolution imaging radar, electronic countermeasures, and so on. The gyro-TWA based on axis encircling electron beam can stably operate at high-order harmonic state, reducing the operating magnetic field linearly proportional with the harmonic number and even achieving superconducting free operation. It can improve the flexibility and maneuverability of gyro-TWA. In this article, a Ka-band second-harmonic gyro-TWA with an interaction circuit of helically corrugated waveguide (HCW) is designed. The simulation results indicate that the gyro-TWT driven by a 75-kV, 7-A axis-encircling electron beam can achieve about 160-kW maximum power with a saturation gain of 29 dB, an efficiency of 30.48%, and a bandwidth of 4 GHz from 27 to 31 GHz. Meanwhile, the design details of the circular polarizer and input coupler are reported.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 10","pages":"5173-5178"},"PeriodicalIF":1.3,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142890231","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-19DOI: 10.1109/TPS.2024.3496908
Ying Cheng;Weihao Liu;Zhengyu Huang;Shaobin Liu;Shangchen Fu
Diminishing the dimensions and weight of high-power microwave (HPM) sources at the gigawatt level holds paramount significance in numerous pragmatic applications. Existing HPM sources typically necessitate a precisely rectangular driving pulse, mandating intricate pulse-forming apparatus for the driving source. In this context, our proposal aims to streamline the driving source and alleviate its weight by advocating the utilization of a readily available dual-exponential voltage pulse to drive an X-band relativistic backward-wave oscillator (RBWO). Through detailed particle-in-cell (PIC) simulations, we examine the operational efficiencies of an RBWO driven by dual-exponential voltage pulses. We delve into the spectral properties, power level, and temporal profiles (including rising time, saturation time, and pulse duration) of the resultant HPM generation driven by a dual-exponential voltage pulse, all meticulously delineated and comparable to conventional rectangular-pulse driving scenarios. Our findings underscore the potential of dual-exponential voltage pulses in driving HPM sources, highlighting their compactness and cost-effectiveness as significant advantages.
{"title":"Investigation on an X-Band Relativistic Backward Wave Oscillator Driven by a Dual-Exponential Voltage Pulse","authors":"Ying Cheng;Weihao Liu;Zhengyu Huang;Shaobin Liu;Shangchen Fu","doi":"10.1109/TPS.2024.3496908","DOIUrl":"https://doi.org/10.1109/TPS.2024.3496908","url":null,"abstract":"Diminishing the dimensions and weight of high-power microwave (HPM) sources at the gigawatt level holds paramount significance in numerous pragmatic applications. Existing HPM sources typically necessitate a precisely rectangular driving pulse, mandating intricate pulse-forming apparatus for the driving source. In this context, our proposal aims to streamline the driving source and alleviate its weight by advocating the utilization of a readily available dual-exponential voltage pulse to drive an X-band relativistic backward-wave oscillator (RBWO). Through detailed particle-in-cell (PIC) simulations, we examine the operational efficiencies of an RBWO driven by dual-exponential voltage pulses. We delve into the spectral properties, power level, and temporal profiles (including rising time, saturation time, and pulse duration) of the resultant HPM generation driven by a dual-exponential voltage pulse, all meticulously delineated and comparable to conventional rectangular-pulse driving scenarios. Our findings underscore the potential of dual-exponential voltage pulses in driving HPM sources, highlighting their compactness and cost-effectiveness as significant advantages.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 10","pages":"5145-5150"},"PeriodicalIF":1.3,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142890229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-18DOI: 10.1109/TPS.2024.3485494
S. Spagnolo;L. Cordaro;N. Pilan;A. De Lorenzi;C. L. Fontana;A. Muraro;T. Patton;F. Pino;G. Croci;R. Gobbo;L. Lotto;I. Mario;E. Martines;D. Rigamonti;E. Spada;M. Tardocchi;M. Zuin
The High Voltage Padova Test Facility (HVPTF) is an experimental device for investigating high voltage (HV) Direct Current insulation in a vacuum, in support of the development of the prototype of a neutral beam injector for ITER, named MITICA. Inside a high vacuum environment, two stainless steel electrodes, spaced by a few centimeters gap, can achieve a voltage difference of up to 800 kV. During the electrode conditioning process, small current bursts, known as micro-discharges (MDs) occur, accompanied by the emission of X-rays, and of an overall increase in gas emission measurement. This study focuses on the fine dynamics of the MD phenomenon measured by the current signal and by the X-ray detectors, in an attempt to provide a possible physical interpretation of this mechanism. In particular, it appears that the MD fine dynamics are related to the growing asymmetry between the MD current values collected by the anode and cathode, observed during the electrode conditioning. The role of the vacuum chamber, acting as a third electrode, is investigated by an updated toy model, which evaluates the different current contributions collected from the two polarized electrodes, particularly those generated by secondary electron (SE) emission. The ratio of anode to cathode currents computed by the toy model closely matches the experimental one. Further experimental observations supporting the hypothesis of anode gas emission and expansion are discussed. Finally, a first study about the statistical distribution of the time intervals between successive MD suggests the occurrence of almost two different trigger mechanisms, evolving during the electrode conditioning process.
{"title":"X-Ray Micro-Discharges Fine Dynamics in a Vacuum High Voltage Experiment","authors":"S. Spagnolo;L. Cordaro;N. Pilan;A. De Lorenzi;C. L. Fontana;A. Muraro;T. Patton;F. Pino;G. Croci;R. Gobbo;L. Lotto;I. Mario;E. Martines;D. Rigamonti;E. Spada;M. Tardocchi;M. Zuin","doi":"10.1109/TPS.2024.3485494","DOIUrl":"https://doi.org/10.1109/TPS.2024.3485494","url":null,"abstract":"The High Voltage Padova Test Facility (HVPTF) is an experimental device for investigating high voltage (HV) Direct Current insulation in a vacuum, in support of the development of the prototype of a neutral beam injector for ITER, named MITICA. Inside a high vacuum environment, two stainless steel electrodes, spaced by a few centimeters gap, can achieve a voltage difference of up to 800 kV. During the electrode conditioning process, small current bursts, known as micro-discharges (MDs) occur, accompanied by the emission of X-rays, and of an overall increase in gas emission measurement. This study focuses on the fine dynamics of the MD phenomenon measured by the current signal and by the X-ray detectors, in an attempt to provide a possible physical interpretation of this mechanism. In particular, it appears that the MD fine dynamics are related to the growing asymmetry between the MD current values collected by the anode and cathode, observed during the electrode conditioning. The role of the vacuum chamber, acting as a third electrode, is investigated by an updated toy model, which evaluates the different current contributions collected from the two polarized electrodes, particularly those generated by secondary electron (SE) emission. The ratio of anode to cathode currents computed by the toy model closely matches the experimental one. Further experimental observations supporting the hypothesis of anode gas emission and expansion are discussed. Finally, a first study about the statistical distribution of the time intervals between successive MD suggests the occurrence of almost two different trigger mechanisms, evolving during the electrode conditioning process.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 9","pages":"4514-4519"},"PeriodicalIF":1.3,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142798019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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