As a flexible auxiliary heating method,the electron cyclotron resonance heating（ECRH） has been widely used in many tokamaks and also will be applied for the J-TEXT tokamak.To meet requirements of protection and faul...As a flexible auxiliary heating method,the electron cyclotron resonance heating（ECRH） has been widely used in many tokamaks and also will be applied for the J-TEXT tokamak.To meet requirements of protection and fault analysis for the ECRH system on J-TEXT,signals of gyrotrons such as the cathode voltage and current,the anode voltage and current,etc should be transmitted to the control and data acquisition system.Considering the high voltage environment of gyrotrons,isolation transmission module based on FPGA and optical fiber communication has been designed and tested.The test results indicate that the designed module has strong anti-noise ability,low error rate and high transmission speed.The delay of the module is no more than 5 μs which can fulfill the requirements.展开更多
Isolated multi-MeV γ-rays with attosecond duration,high collimation and beam angular momentum(BAM)may find many interesting applications in nuclear physics,astrophysics,etc.Here,we propose a scheme to generate such ...Isolated multi-MeV γ-rays with attosecond duration,high collimation and beam angular momentum(BAM)may find many interesting applications in nuclear physics,astrophysics,etc.Here,we propose a scheme to generate such γ-rays via nonlinear Thomson scattering of a rotating relativistic electron sheet driven by a few-cycle twisted laser pulse interacting with a micro-droplet target.Our model clarifies the laser intensity threshold and carrier-envelope phase effect on the generation of the isolated electron sheet.Three-dimensional numerical simulations demonstrate the γ-ray emission with 320 attoseconds duration and peak brilliance of 9.3×10^(24)photons s^(-1)mrad^(-2)mm^(-2)per 0.1%bandwidth at 4.3 MeV.The γ-ray beam carries a large BAM of 2.8×10^(16)■,which arises from the efficient BAM transfer from the rotating electron sheet,subsequently leading to a unique angular distribution.This work should promote the experimental investigation of nonlinear Thomson scattering of rotating electron sheets in large laser facilities.展开更多
基金supported by the ITER Special Fund of China(Grant Nos.2013GB106001 and 2013GB106003)
文摘As a flexible auxiliary heating method,the electron cyclotron resonance heating（ECRH） has been widely used in many tokamaks and also will be applied for the J-TEXT tokamak.To meet requirements of protection and fault analysis for the ECRH system on J-TEXT,signals of gyrotrons such as the cathode voltage and current,the anode voltage and current,etc should be transmitted to the control and data acquisition system.Considering the high voltage environment of gyrotrons,isolation transmission module based on FPGA and optical fiber communication has been designed and tested.The test results indicate that the designed module has strong anti-noise ability,low error rate and high transmission speed.The delay of the module is no more than 5 μs which can fulfill the requirements.
基金supported by the National Natural Science Foundation of China(Nos.12105362,12375244,12275356,12135009,U2241281 and 12175310)the Natural Science Foundation of Hunan Province(No.2022JJ20042)the Innovation Foundation for Graduate Students(No.CX20220048)
文摘Isolated multi-MeV γ-rays with attosecond duration,high collimation and beam angular momentum(BAM)may find many interesting applications in nuclear physics,astrophysics,etc.Here,we propose a scheme to generate such γ-rays via nonlinear Thomson scattering of a rotating relativistic electron sheet driven by a few-cycle twisted laser pulse interacting with a micro-droplet target.Our model clarifies the laser intensity threshold and carrier-envelope phase effect on the generation of the isolated electron sheet.Three-dimensional numerical simulations demonstrate the γ-ray emission with 320 attoseconds duration and peak brilliance of 9.3×10^(24)photons s^(-1)mrad^(-2)mm^(-2)per 0.1%bandwidth at 4.3 MeV.The γ-ray beam carries a large BAM of 2.8×10^(16)■,which arises from the efficient BAM transfer from the rotating electron sheet,subsequently leading to a unique angular distribution.This work should promote the experimental investigation of nonlinear Thomson scattering of rotating electron sheets in large laser facilities.
