Speaker
M. J. Pueschel
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/O3.J403.pdf
Electron-Positron Plasma Turbulence Driven by Pressure Gradients
M.J. Pueschel1,2 , P.W. Terry2 , F. Jenko1,3 , and B. Tyburska-Pueschel2,4
1 University of Texas at Austin, Austin, Texas 78712, USA
2 University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
3 Max Planck Institute for Plasma Physics, 85748 Garching, Germany
4 German Aerospace Center, 51147 Cologne, Germany
The stability and turbulence properties of pair plasmas are of significant consequence in
many, disparate physical systems. Fluctuations may appear in laser-induced or magnetically
confined pair plasmas, and electron-positron plasma turbulence may affect the radiation signa-
ture of objects such as Gamma Ray Bursts (GRBs).
Here, the focus lies on electron-positron plasmas in a strong, homogeneous magnetic guide
field, subject to a background density or temperature gradient. It is shown that this setup allows
the E×B and ∇Bk drifts to couple, causing instability. This process is referred to as the Gradient-
driven Drift Coupling (GDC) mode [1], which is also able to drive turbulence in helium plasma
experiments [2].
Unlike standard fluid models, which do not include a succinct description of the ∇Bk drift,
a new fluid model is presented that recovers gyrokinetic analytical and numerical mode prop-
erties. Furthermore, nonlinear gyrokinetic simulation results are shown, demonstrating that the
GDC instability may indeed drive quasi-stationary turbulence in pair plasmas.
Consequences are discussed for specific physical systems: in addition to GRBs, the focus lies
on high-density, laser-induced pair plasma experiments [3] – assuming the addition, presently
under discussion, of a magnetic guide field – and low-density, zero-shear magnetic-confinement
experiments [4].
References
[1] M.J. Pueschel, P.W. Terry, D. Told, and F. Jenko, Phys. Plasmas 22, 062105 (2015)
[2] M.J. Pueschel et al., Plasma Phys. Control. Fusion 59, 024006 (2017)
[3] G. Sarri et al., Nat. Commun. 6, 6747 (2015)
[4] H. Saitoh et al., J. Phys. Conf. Ser. 505, 012045 (2014)
