@article{DieckmannSarriDoriaetal.2013,
  author    = {Dieckmann, M. E. and Sarri, G. and Doria, D. and Pohl, Martin and Borghesi, M.},
  title     = {Modification of the formation of high-mach number electrostatic shock-like structures by the ion acoustic instability},
  series = {Physics of plasmas},
  volume    = {20},
  journal   = {Physics of plasmas},
  number    = {10},
  publisher = {American Institute of Physics},
  address   = {Melville},
  issn      = {1070-664X},
  doi       = {10.1063/1.4825339},
  pages     = {12},
  year      = {2013},
  abstract  = {The formation of unmagnetized electrostatic shock-like structures with a high Mach number is examined with one-and two-dimensional particle-in-cell (PIC) simulations. The structures are generated through the collision of two identical plasma clouds, which consist of equally hot electrons and ions with a mass ratio of 250. The Mach number of the collision speed with respect to the initial ion acoustic speed of the plasma is set to 4.6. This high Mach number delays the formation of such structures by tens of inverse ion plasma frequencies. A pair of stable shock-like structures is observed after this time in the 1D simulation, which gradually evolves into electrostatic shocks. The ion acoustic instability, which can develop in the 2D simulation but not in the 1D one, competes with the nonlinear process that gives rise to these structures. The oblique ion acoustic waves fragment their electric field. The transition layer, across which the bulk of the ions change their speed, widens and their speed change is reduced. Double layer-shock hybrid structures develop.},
  language  = {en}
}
@article{DieckmannAhmedSarrietal.2013,
  author    = {Dieckmann, M. E. and Ahmed, H. and Sarri, G. and Doria, D. and Kourakis, I. and Romagnani, L. and Pohl, Martin and Borghesi, M.},
  title     = {Parametric study of non-relativistic electrostatic shocks and the structure of their transition layer},
  series = {Physics of plasmas},
  volume    = {20},
  journal   = {Physics of plasmas},
  number    = {4},
  publisher = {American Institute of Physics},
  address   = {Melville},
  issn      = {1070-664X},
  doi       = {10.1063/1.4801447},
  pages     = {10},
  year      = {2013},
  abstract  = {Nonrelativistic electrostatic unmagnetized shocks are frequently observed in laboratory plasmas and they are likely to exist in astrophysical plasmas. Their maximum speed, expressed in units of the ion acoustic speed far upstream of the shock, depends only on the electron-to-ion temperature ratio if binary collisions are absent. The formation and evolution of such shocks is examined here for a wide range of shock speeds with particle-in-cell simulations. The initial temperatures of the electrons and the 400 times heavier ions are equal. Shocks form on electron time scales at Mach numbers between 1.7 and 2.2. Shocks with Mach numbers up to 2.5 form after tens of inverse ion plasma frequencies. The density of the shock-reflected ion beam increases and the number of ions crossing the shock thus decreases with an increasing Mach number, causing a slower expansion of the downstream region in its rest frame. The interval occupied by this ion beam is on a positive potential relative to the far upstream. This potential pre-heats the electrons ahead of the shock even in the absence of beam instabilities and decouples the electron temperature in the foreshock ahead of the shock from the one in the far upstream plasma. The effective Mach number of the shock is reduced by this electron heating. This effect can potentially stabilize nonrelativistic electrostatic shocks moving as fast as supernova remnant shocks.},
  language  = {en}
}