摘要
为了探索超热电子的加热机制,利用光学CCD相机和OMA光学多道分析仪,分别在靶背法线方向测量了光学渡越辐射(OTR)积分成像图案和光谱。实验在100TW掺钛蓝宝石激光器上进行,飞秒激光与铜膜靶作用后,靶表面发光信号由空间分辨装置聚焦成像并引到CCD或OMA谱仪的狭缝上。测得的积分成像图案呈圆环状,光斑形成区域直径约为225μm,在圆环边缘附近出现局部化明亮光信号,该现象表明,超热电子在传输的过程中存在成丝效应,其分布也不均匀。光谱在300～500nm之间出现一系列非周期锐利尖峰,在400nm(2ω0)附近出现的尖峰应归因于v×B加热机制产生的超热电子引起的相干渡越辐射(CTR)。
For rearching the acceleration mechanism of hot electron, the integrated image pattern and spectrum of optical transition radiation (OTR) were measured at the normal direction from the rear side of targets employing optical CCD camera and OMA optical multi-channel spectrometer. The experiment was carried out on the 100 TW laser. The measured integrated image pattern presents a ring-shape of about 225 μm in diameter. In the near edge of the ring-shape there is a bright localized signal, which indicates filament effect exists during hot electron transport. The spectrum presents a series of nonperiodic sharp peaks between 300-500 nm, which is attributed to the coherent transition radiation (CTR) of hot electron generated by v × B acceleration mechanism near 400 nm (2ω0).
出处
《强激光与粒子束》
EI
CAS
CSCD
北大核心
2005年第6期871-874,共4页
High Power Laser and Particle Beams
基金
国家自然科学基金资助课题(10275055
10275056)
高等学校博士点基金资助课题(200220610001)
关键词
光学渡越辐射
超热电子
成丝效应
v×B加热机制
相干渡越辐射
Acceleration
Cameras
Charge coupled devices
Electron irradiation
Filaments (lamp)
Spectrometers
Targets
Ultrashort pulses
