Relativistic fast electrons are generated in the interaction of ultrashort (tens of fs) ultrahigh intensity laser (>1018W/cm2) pulses with solid target.Investigation of thegeneration and transport of fast electrons in solid material is a subject of intense research investigation not only for fundamental understanding of laser matter interaction in extreme condition but also for various...
During the last few years, IHEP plasma-based acceleration study group dedicated its time on both laser wakefield acceleration (LWFA) and plasma wakefield acceleration (PWFA).
In LWFA, we mainly focused on injection mechanism studies to improve the beam quality. Different injection schemes such as scissors-cross ionization injection, coaxial laser interference induced injection, tightly...
Based on the NCU 100-TW laser system, we use the hybrid scheme, proposed by Isayama et al, using dual laser pulses to drive 53 MeV protons. The dual pulses are identical (810-nm wavelength, 1.5-J energy, 30-fs pulse duration, and 5-micron spot size). The target is composed of a solid-density target and a near-critical density target.
This hybrid scheme combines the three typical schemes: RPA,...
Developing an effective method for the injection and acceleration of positrons in plasma wakefield acceleration has been a persistent issue due to the lack of appropriate wakefield structure. We show that the plasma wakefield driven by a hollow proton beam forms an electron filament along the axis, thus providing the acceleration and focusing fields required by positrons. The evolution of the...
X-rays have extensive applications in biomedical research, physics, and materials science. The Laser Wakefield Accelerator (LWFA) is one of the methods capable of generating X-rays, featuring the advantage of a small footprint. This makes it more convenient for laboratories, hospitals, and other facilities to observe structures such as crystals, drugs, and proteins. The experiment uses the NCU...
The laser wake-field acceleration (LWFA) provides energetic electron beams with higher acceleration gradient. The typical strength of the electrostatic field reaches GV/cm. Significant developments have been achieved in the past decades and various mechanisms have been proposed for beam quality improving. LWFA is expected to deliver high quality electron beams for potential applications....
We present LCODE 3D, a new tool that allows for simulations of plasma wakefield acceleration in three-dimensional geometry using a quasi-static approximation. Based on the principles of the time-tested LCODE 2D code, LCODE 3D offers the flexibility of switching between different geometries, allowing for efficient work when three-dimensional effects have minimal impact. Furthermore, LCODE 3D is...
Recently, there has been considerable attention on high-polarization table-top hard X-ray sources, which facilitate easy deployment in clinics and university laboratories, providing convenient access to results regarding material microstructures or properties. Betatron radiation, one of the X-ray sources that has femtosecond range duration, μm spot size, and compact equipment, is considered an...
Quasistatic approximation (QSA) offers opportunities for computationally efficient modeling of laser pulse propagation over long distances. When simulating the channeling of a powerful laser pulse over tens of meters (studied in the context of XCELS project), the QSA gives a speedup of six orders of magnitude compared to the particle-in-cell method. This estimate takes into account the need to...
By introducing the electron-optic Sampling technique in to the research of laser Wakefield acceleration, we have conducted single-shot spatial-temporal detection on the electron bunches.In our recent experiments, we have measured the electron timing fluctuation at a position outside the plasma. By simultaneously performing optical transition radiation imaging and EO spatial decoding, the...
Fabricating a thin, dense gas target capable of providing a plasma electron density of > 10^{19} cm^{-3} enables the operation of laser wakefield acceleration (LWFA) with few-TW or even sub-TW pulses, as a strong laser intensity can be achieved for the self-focused and self-modulated pump pulse to drive plasma waves for electron acceleration. The high plasma density used here, however, results...
Simulations of plasma wakefield acceleration are challenging for many reasons, one of which is that the wave scale (about plasma skin depth) is much larger than the Debye length. Attempting to resolve both would make simulations prohibitively expensive. Therefore, grid steps far exceeding the Debye length are used, which compromises the accuracy of PIC simulations. While this inconsistency...
Plasma wakefield acceleration is a promising technology for compact particle acceleration, experimental results demonstrating a high-quality beam reaching 1GeV energy in just 3.3cm [1]. Simulations are a key tool used to develop our understanding of plasma wakefield technologies, however, conventional particle-in-cell (PIC) codes can be arduous to run, requiring significant computing power....
Terahertz (THz)-driven accelerators are emerging as promising compact particle accelerators. By using higher frequency drivers, the threshold of vacuum breakdown can be significantly increased. Consequently, it is anticipated that the accelerating gradient can be enhanced, projecting an increase from the current 100 MV/m-order to 1 GV/m-class. To generate the high-field THz waves, laser-driven...
The China Spallation Neutron Source (CSNS) delivers a pulsed neutron beam at a 25Hz repetition rate, necessitating precise data synchronization for effective beam state analysis and fault diagnosis. This work presents the development of a Beam-Synchronized Data Acquisition (BSDAQ) system tailored for the CSNS accelerator. The BSDAQ system is engineered to selectively capture critical...
We have developed a new segmented capillary gas cell for laser wakefield acceleration (LWFA) and plasma lenses. This capillary enables the tailoring of longitudinal density profiles in gases or plasmas, with a transverse guiding structure when discharged with high-voltage pulses. For instance, a down-gradient density profile can be used for controlled injection in LWFA. We tested this...
The pulse duration of the X-ray free-electron laser (XFEL) relies on the pulse duration of the light source, which commonly is an electron bunch. The energy and the current distributions of the electron bunch can be manipulated by using the laser heater in the purpose of generating attosecond pulse duration electron bunch. Therefore, the resultant electron bunch current profile after the bunch...
