1 Introduction of neutral beam injection system on HL-2A The neutral beam injection （NBI） system on HL-2A includes two beam-lines about 8 meters long. Each beam-line consists of four ion sources. The ion source is ...1 Introduction of neutral beam injection system on HL-2A The neutral beam injection （NBI） system on HL-2A includes two beam-lines about 8 meters long. Each beam-line consists of four ion sources. The ion source is the key component of neutral beam injector. It can be divided into two parts, an arc chamber and an accelerator system. The main parameters of HL-2A NBI system are the injection energy of 60 keV, maximum ion extraction power of 3 MW, beam power of 2 MW and pulse duration of 2 s. The beam line is tangentially injected into plasma along torus mid-plane. The angle between beam line and major radius is 37.7° at injection port.展开更多
This report consists of two main research activities ： The first one is the study of MHD ballooning stability of tokamak plasmas, the second is about some fundamental aspect in the ECR wave propagation and power depo...This report consists of two main research activities ： The first one is the study of MHD ballooning stability of tokamak plasmas, the second is about some fundamental aspect in the ECR wave propagation and power deposition. Main results are summarized here in three parts briefly. In the first part, the instabilities of tokamak plasma in the negative shear regime is studied and characteristics of the unstable mode is described, the scaling law of the growth rate over plasma parameters is given. In the second part, by using the restrict Solov＇ev configuration, the correctness of the usual s,α model in ballooning mode theory is analyzed. In the third part, the deposition of the power density of the ECR ordinary wave in the HL-2A plasma is calculated.展开更多
In the last year, ECRH system has been built in the HL-2A and the testing of gyrotron is also finished. In the project testing, one of the problems is current-peak occurring in the anode circuit of gyrotron. The curre...In the last year, ECRH system has been built in the HL-2A and the testing of gyrotron is also finished. In the project testing, one of the problems is current-peak occurring in the anode circuit of gyrotron. The current-peak is much larger than that of the value set in protection circuit. The frequent current-peak frequently occurring in the rising of anode-voltage often caused the protection circuit to mistaken trigger. The mistaken triggering often halted the normal gyrotron-testing. A set of equations of anode circuit are derived for analysis the phenomena of the current-peak. The calculation based on the deduced formula shows that value of the current-peak strongly depends on the inductance L, capacitance C and the ramp-time of anode voltage in the anode circuit. The conductance L and capacitance C are the characteristic inductance and capacitance of the cable that is used for anode HV power supply. The numerical calculation is exactly consistent with waveform of the current peak recorded by oscillograph, that means the derived formula are correct. In order to decrease the value of the current-peak, we should decrease capacitance C, and increase inductance L and ramp-time of anode voltage.展开更多
This paper shows the R＆D results of the power supply system in 2006, including the application of speed control assemblies of two 80 MVA MG sets, the modification of the exciting field system, the development of the ...This paper shows the R＆D results of the power supply system in 2006, including the application of speed control assemblies of two 80 MVA MG sets, the modification of the exciting field system, the development of the new HV modulators in ECRH system, the update of several poloidal power supplies. It also presents the status of the power suppIy system in HL-2A experimental operation and foresees the power and energy requirements for new power supply system at HL-2M device.展开更多
Soft X-ray emission from tokamak plasma is dependent on various plasma parameters, such as density and temperature, and one can thus infer information about them by observing this radiation. For multi-channel diagnost...Soft X-ray emission from tokamak plasma is dependent on various plasma parameters, such as density and temperature, and one can thus infer information about them by observing this radiation. For multi-channel diagnostics, computed tomography is necessary to reconstruct the 2-D spatial distribution of the emission intensity g（r,θ） in a plasma. Therefore, soft X-ray tomography has become an important tool to study various phenomena in fusion plasma, such as sawtoothing, m = 1 precursor oscillation, snake, m ≥ 2 instabilities, and disruption, as well as plasma position, impurity radiation, etc.展开更多
A three-tip array is used in the HL-2A tokamak to investigate the spectral characteristics of electrostatic turbulence inside the last closed flux surface （LCFS） about 5 cm. Two-point correlation techniques are used...A three-tip array is used in the HL-2A tokamak to investigate the spectral characteristics of electrostatic turbulence inside the last closed flux surface （LCFS） about 5 cm. Two-point correlation techniques are used to analysis the turbulence structure. It is found that the drift wave turbulence mainly is composed of low-frequency and long wavelength wave packets. The poloidal propagation is mainly in electron-diamagnetic direction, sometimes it propagates in ion-diamagnetic direction, which is influenced by Doppler-frequency shift. The radial propagation velocity is outward and the sizeable fraction of the poloidal velocity, implying that the radial mode plays an important role in the cross field transport.展开更多
In this experiment, the electrostatic probes positioned on the divertor plates and at the edge of main vacuum chamber, which are used to measure plasma parameters. All these parameters are used to investigate the edge...In this experiment, the electrostatic probes positioned on the divertor plates and at the edge of main vacuum chamber, which are used to measure plasma parameters. All these parameters are used to investigate the edge turbulence and correlative characteristic. A large number of experimental results suggest that the confinement improvement is related to the increasing rotation velocity and to the decreasing edge fluctuation.展开更多
The tokamak disruption is a dramatic event in which the plasma confinement is suddenly destroyed. Detailed experimental studies of disruptions have been made in many machines. During disruption, the plasma current and...The tokamak disruption is a dramatic event in which the plasma confinement is suddenly destroyed. Detailed experimental studies of disruptions have been made in many machines. During disruption, the plasma current and plasma thermal energy content collapse in an uncontrollable way, thereby applying mechanical forces and heat loads onto the vacuum vessel components. For that reason, the disruptions in a tokamak must be investigated and the physical processes leading to and occurring at the disruption need to be understood.展开更多
In 2006, the following work on secondary heating systems for HL-2A tokamak have been done： the development of an electron cyclotron resonance heating （ECRH） system, the improvement of lower hybrid resonance heating...In 2006, the following work on secondary heating systems for HL-2A tokamak have been done： the development of an electron cyclotron resonance heating （ECRH） system, the improvement of lower hybrid resonance heating （LHCD） system and the fabrication on neutral beam injection （NBI） system.展开更多
文摘1 Introduction of neutral beam injection system on HL-2A The neutral beam injection （NBI） system on HL-2A includes two beam-lines about 8 meters long. Each beam-line consists of four ion sources. The ion source is the key component of neutral beam injector. It can be divided into two parts, an arc chamber and an accelerator system. The main parameters of HL-2A NBI system are the injection energy of 60 keV, maximum ion extraction power of 3 MW, beam power of 2 MW and pulse duration of 2 s. The beam line is tangentially injected into plasma along torus mid-plane. The angle between beam line and major radius is 37.7° at injection port.
基金Supported by the National Natural Science Foundation of China （10375018）
文摘This report consists of two main research activities ： The first one is the study of MHD ballooning stability of tokamak plasmas, the second is about some fundamental aspect in the ECR wave propagation and power deposition. Main results are summarized here in three parts briefly. In the first part, the instabilities of tokamak plasma in the negative shear regime is studied and characteristics of the unstable mode is described, the scaling law of the growth rate over plasma parameters is given. In the second part, by using the restrict Solov＇ev configuration, the correctness of the usual s,α model in ballooning mode theory is analyzed. In the third part, the deposition of the power density of the ECR ordinary wave in the HL-2A plasma is calculated.
文摘In the last year, ECRH system has been built in the HL-2A and the testing of gyrotron is also finished. In the project testing, one of the problems is current-peak occurring in the anode circuit of gyrotron. The current-peak is much larger than that of the value set in protection circuit. The frequent current-peak frequently occurring in the rising of anode-voltage often caused the protection circuit to mistaken trigger. The mistaken triggering often halted the normal gyrotron-testing. A set of equations of anode circuit are derived for analysis the phenomena of the current-peak. The calculation based on the deduced formula shows that value of the current-peak strongly depends on the inductance L, capacitance C and the ramp-time of anode voltage in the anode circuit. The conductance L and capacitance C are the characteristic inductance and capacitance of the cable that is used for anode HV power supply. The numerical calculation is exactly consistent with waveform of the current peak recorded by oscillograph, that means the derived formula are correct. In order to decrease the value of the current-peak, we should decrease capacitance C, and increase inductance L and ramp-time of anode voltage.
文摘This paper shows the R＆D results of the power supply system in 2006, including the application of speed control assemblies of two 80 MVA MG sets, the modification of the exciting field system, the development of the new HV modulators in ECRH system, the update of several poloidal power supplies. It also presents the status of the power suppIy system in HL-2A experimental operation and foresees the power and energy requirements for new power supply system at HL-2M device.
文摘Soft X-ray emission from tokamak plasma is dependent on various plasma parameters, such as density and temperature, and one can thus infer information about them by observing this radiation. For multi-channel diagnostics, computed tomography is necessary to reconstruct the 2-D spatial distribution of the emission intensity g（r,θ） in a plasma. Therefore, soft X-ray tomography has become an important tool to study various phenomena in fusion plasma, such as sawtoothing, m = 1 precursor oscillation, snake, m ≥ 2 instabilities, and disruption, as well as plasma position, impurity radiation, etc.
基金Supported by National Natural Science Foundation of China （10675041） First authors would give thanks to the HL-2A team for steady state discharges.
文摘A three-tip array is used in the HL-2A tokamak to investigate the spectral characteristics of electrostatic turbulence inside the last closed flux surface （LCFS） about 5 cm. Two-point correlation techniques are used to analysis the turbulence structure. It is found that the drift wave turbulence mainly is composed of low-frequency and long wavelength wave packets. The poloidal propagation is mainly in electron-diamagnetic direction, sometimes it propagates in ion-diamagnetic direction, which is influenced by Doppler-frequency shift. The radial propagation velocity is outward and the sizeable fraction of the poloidal velocity, implying that the radial mode plays an important role in the cross field transport.
文摘In this experiment, the electrostatic probes positioned on the divertor plates and at the edge of main vacuum chamber, which are used to measure plasma parameters. All these parameters are used to investigate the edge turbulence and correlative characteristic. A large number of experimental results suggest that the confinement improvement is related to the increasing rotation velocity and to the decreasing edge fluctuation.
文摘The tokamak disruption is a dramatic event in which the plasma confinement is suddenly destroyed. Detailed experimental studies of disruptions have been made in many machines. During disruption, the plasma current and plasma thermal energy content collapse in an uncontrollable way, thereby applying mechanical forces and heat loads onto the vacuum vessel components. For that reason, the disruptions in a tokamak must be investigated and the physical processes leading to and occurring at the disruption need to be understood.
文摘In 2006, the following work on secondary heating systems for HL-2A tokamak have been done： the development of an electron cyclotron resonance heating （ECRH） system, the improvement of lower hybrid resonance heating （LHCD） system and the fabrication on neutral beam injection （NBI） system.
