- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Brief History of the EML Symposia: 1980-2018
摘要： Following the pioneering research studies by individual inventors and teams from the 1840s to the 1960s on various aspects of electromagnetic launch using railguns, coilguns, and linear motors, there has been an explosion of interest since the 1970s. Much of this growth has been discussed at the International Electro-Magnetic Launcher Symposia that have taken place approximately every two years from 1980 to 2018. A brief description and a summary of the early work of pioneers in this field as well as the symposia is provided here. Selected papers from the symposia have been archived in the IEEE TRANSACTIONS ON MAGNETICS and the IEEE TRANSACTIONS ON PLASMA SCIENCE.
关键词： linear launchers,electro-magnetic launcher (EML) Symposia,railguns,pulsed power,electromagnetic (EM) launchers,Coilguns
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE International Power Modulator and High Voltage Conference (IPMHVC) - Jackson, WY, USA (2018.6.3-2018.6.7)] 2018 IEEE International Power Modulator and High Voltage Conference (IPMHVC) - Solid State Laser Triggering System for the HERMES-III Accelerator
摘要： The Hermes III accelerator is a 20-MV linear induction accelerator that has been in operation at Sandia National Laboratories since the late 1980’s. Energy is initially stored in the accelerator in ten Marx banks that are discharged into twenty intermediate store capacitors. These intermediate store capacitors are then switched with SF6-insulated high voltage Rimfire switches into eighty parallel pulse forming lines that further condition the pulse before finally delivering it to the twenty induction cavities arrayed along the axis of the machine. Currently, a single 0.9-J KrF laser operating at 248 nm, the output of which is divided into twenty separate beamlets, is being used to trigger the Rimfire switches. However, as part of a modernization plan for the accelerator, the gas laser system is being replaced with a new solid-state laser triggering system. The new system is comprised of 10 flash-lamp pumped, Q-switched Nd:YAG lasers (Tempest 300), each having an energy output of 35~40 mJ at a wavelength of 266 nm. Each laser will be responsible for triggering two Rimfire switches. Overall reliability for the accelerator’s operation with these new lasers is expected to increase, and by varying the times at which the individual lasers fire it becomes possible to tailor the shape of the output pulse. The optical layout and other details of this solid-state laser triggering system are presented, along with initial operational data from the HERMES III accelerator using this system.
关键词： Rimfire switches,laser triggered switches,pulsed power accelerator,solid-state lasers
更新于2025-09-19 17:13:59
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The spatial-temporal distribution of the electron density and temperature in nanosecond pulsed discharge plasma measured by laser Thomson scattering
摘要： The spatial-temporal distribution of the electron temperature (Te) and density (ne) in a nanosecond pulsed discharge (NPD) argon plasma with a ball-to-plate electrode con?guration at 2 × 103 Pa has been measured by Laser Thomson Scattering (LTS). The peak voltage between two electrodes is 1520 V and the current is 3 A when the ball-like electrode is connected to the negative high voltage. The results indicate that it is possible to enhance the electron density of the plasma discharge using the rising edge of pulse voltage. The measured plasma parameters: Te decreases exponentially from 1.75 eV to 0.1 eV and ne increases rapidly to 3.94 × 1020 m?3 from 15 ns to 115 ns then decreases to 1.17 × 1019 m?3. In the discharge with cylindrical geometric symmetry, Te increases from ball to plate, while ne is opposite. In the r-direction, both Te and ne decrease from central to edge at 3.4 mm. Value of ne varies by 20 times from maximum to minimum and Te is only about 1.5 times.
关键词： Plasma diagnostics - interferometry, spectroscopy and imaging,Pulsed power
更新于2025-09-16 10:30:52
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[IEEE 2019 21st European Conference on Power Electronics and Applications (EPE '19 ECCE Europe) - Genova, Italy (2019.9.3-2019.9.5)] 2019 21st European Conference on Power Electronics and Applications (EPE '19 ECCE Europe) - Laser triggering of solid-state switches
摘要： A theoretical and experimental investigation has been made into the laser activated Silicon Controlled Rectifier (SCR) turn-on process. Thanks to the measurement of illumination profile of the thyristor gate and a one-dimensional commutation model, a prediction can be made of the temperature hotspots of the initially conducting area region adjacent to the gate. The improvement of switching characteristics with respect to the datasheet parameters for an electrically gated configuration will be demonstrated; 8-fold turn-on delay reduction and the rate of rise of the on-state current (di/dt) increased over 45 times at low pulse repetition rate, without destroying the device.
关键词： New switching devices,Thyristors,Photovoltaic,Switching losses,Particle accelerator,Transistor,Pulsed power,Semiconductor device
更新于2025-09-16 10:30:52
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Comprehensive diagnostics of hot electron emission from plasmas produced by sub-nanosecond terawatt laser on thin foil metal targets
摘要： Interaction of high-power and high-energy lasers with matter generates plasmas emitting considerable amounts of relativistic electrons. In this contribution such plasmas were produced by PALS kJ laser facility delivering the beam with intensity of the order of 3 · 1016 W · cm?2 in 400 ps on thin foil metal targets. To study the emission of hot electrons in horizontal plane around the target, an array of electron spectrometers was employed to record the electron emission from the plasma in several angles around the target. For experimental determination of the total number of hot electrons escaping from the plasma through the plasma barrier a target probe was used in order to measure the target return current which neutralizes the positive target charge produced by these escaping hot electrons. Together with this diagnostics the femtosecond interferometry was used to obtain spatial electron density pro?les in close proximity to the irradiated target at selected time delays. Interferograms indicated occurrence of plasma density modulations in front of the target and made it possible to calculate the number of electrons contained within thermal fraction of the plasma produced by the laser. The number of these electrons correlates with the ?ux of soft x-ray radiation observed with the use of an x-ray streak camera.
关键词： Plasma diagnostics - probes,Pulsed power,Interaction of radiation with matter,Plasma diagnostics - interferometry, spectroscopy and imaging
更新于2025-09-12 10:27:22
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Compact pulsed intense magnetic field generator for Shenguang-II upgrade laser facility
摘要： A compact pulsed intense magnetic field generator is presented for magnetized laser plasma experiments at the Shenguang-II upgrade laser facility (Shanghai). The pulsed magnetic field device can generate a 45 kA peak current with 480 ns rising time at a discharge voltage of 40 kV, time jitter is about 100 ns. The peak magnetic field reaches 9 T using a double-twisted coil of 12 mm diameter. A specially designed tunable transmission line was developed to realize the flexible connection between the capacitor bank and the magnetic field coil. The setup is compatible with the particular target chamber of the laser facility. Thus the coil component can be adjusted separately by the three-dimensional motorized translation stage placed in the target chamber, with 10 cm (transverse) and 1 cm (longitudinal) adjustable scales and 6 μm precision. A high-voltage electric-trigger spark-gap gas switch was used to reduce the operation complexity and the occupied area of the generator. Grounding and shielding structure ensure fine electromagnetic compatibility with the target chamber. The device has been successfully operated in magnetized laser plasma experiments performed on the laser facility.
关键词： Special cables,Pulsed power,Plasma generation (laser-produced, RF, x ray-produced)
更新于2025-09-12 10:27:22
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Superlattice-enhanced silicon soft X-ray and charged particle detectors with nanosecond time response
摘要： Silicon detectors are an essential measurement tool for Inertial Confinement Fusion and High-Energy-Density Physics Applications, where temporal response of the order of nanoseconds is essential. Soft X-rays (<1 keV), Ultraviolet light, and low-energy electrons (<10 keV) can provide essential information in diagnosing rapidly changing plasma conditions, but reducing the detector dead layer is essential to improving detector response for these shallowly absorbed particles. This paper details a study of silicon detector surface preparation methods such as ion implant parameters, and the addition of a quantum 2D superlattice, to produce fast detectors that are highly sensitive to shallowly absorbed radiation. Measurements of visible light quantum efficiency, electron responsivity, and pulsed x-ray response indicate that detectors with a 2-layer superlattice enjoy a significant benefit over equivalent detectors using an ion implant at the illuminated surface.
关键词： Pulsed power,ICF,HED physics,Silicon detectors,Electron detectors,Soft X-ray detectors
更新于2025-09-09 09:28:46