@article{ChenLoischGrossetal.2018,
  author    = {Chen, Ye and Loisch, Gregor and Gross, Matthias and Jao, Chun-Sung and Krasilnikov, Mikhail and Oppelt, Anne and Osterhoff, Jens and Pohl, Martin and Qian, Houjun and Stephan, Frank and Vafin, Sergei},
  title     = {Generation of quasi continuous-wave electron beams in an L-band normal conducting pulsed RF injector for laboratory astrophysics experiments},
  series = {Nuclear instruments \& methods in physics research : a journal on accelerators, instrumentation and techniques applied to research in nuclear and atomic physics, materials science and related fields in physics ; A, Accelerators, spectrometers, detectors and associated equipment},
  volume    = {903},
  journal   = {Nuclear instruments \& methods in physics research : a journal on accelerators, instrumentation and techniques applied to research in nuclear and atomic physics, materials science and related fields in physics ; A, Accelerators, spectrometers, detectors and associated equipment},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0168-9002},
  doi       = {10.1016/j.nima.2018.06.063},
  pages     = {119 -- 125},
  year      = {2018},
  abstract  = {We report on an approach to produce quasi continuous-wave (cw) electron beams with an average beam current of milliamperes and a mean beam energy of a few MeV in a pulsed RF injector. Potential applications are in the planned laboratory astrophysics programs at DESY. The beam generation is based on field emission from a specially designed metallic field emitter. A quasi cw beam profile is formed over subsequent RF cycles at the resonance frequency of the gun cavity. This is realized by debunching in a cut disk structure accelerating cavity (booster) downstream of the gun. The peak and average beam currents can be tuned in beam dynamics simulations by adjusting operation conditions of the booster cavity. Optimization of the transverse beam size at specific positions (e.g., entrance of the plasma experiment) is performed by applying magnetic focusing fields provided by solenoids along the beam line. In this paper, the design of a microtip field emitter is introduced and characterized in electromagnetic field simulations in the gun cavity. A series of particle tracking simulations are conducted for multi-parametric optimization of the parameters of the produced quasi cw electron beams. The obtained results will be presented and discussed. In addition, measurements of the parasitic field emission (PFE) current (dark current) in the PITZ gun will be exemplarily shown to distinguish its order of magnitude from the produced beam current by the designed field emitter.},
  language  = {en}
}
@article{JaoVafinChenetal.2019,
  author    = {Jao, Chun-Sung and Vafin, Sergei and Chen, Ye and Gross, Matthias and Krasilnikov, Mikhail and Loisch, Gregor and Mehrling, Timon and Niemiec, Jacek and Oppelt, Anne and de la Ossa, Alberto Martinez and Osterhoff, Jens and Pohl, Martin and Stephan, Frank},
  title     = {Preliminary study for the laboratory experiment of cosmic-rays driven magnetic field amplification},
  series = {High Energy Density Physics},
  volume    = {32},
  journal   = {High Energy Density Physics},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1574-1818},
  doi       = {10.1016/j.hedp.2019.04.001},
  pages     = {31 -- 43},
  year      = {2019},
  abstract  = {To understand astrophysical magnetic-field amplification, we conducted a feasibility study for a laboratory experiment of a non-resonant streaming instability at the Photo Injector Test Facility at DESY, Zeuthen site (PITZ). This non-resonant streaming instability, also known as Bell's instability, is generally regarded as a candidate for the amplification of interstellar magnetic field in the upstream region of supernova-remnant shocks, which is crucial for the efficiency of diffusive shock acceleration. In the beam-plasma system composed of a radio-frequency electron gun and a gas-discharge plasma cell, the goal of our experiment is to demonstrate the development of the non-resonant streaming instability and to find its saturation level in the laboratory environment. Since we find that the electron beam will be significantly decelerated on account of an electrostatic streaming instability, which will decrease the growth rate of desired non-resonant streaming instability, we discuss possible ways to suppress the electrostatic streaming instability by considering the characteristics of a field-emission-based quasi continuous-wave electron beam.},
  language  = {en}
}