  Electromagnetic turbulence and ion kinetics in counter-streaming plasmas hold
great significance in laboratory astrophysics, such as turbulence field
amplification and particle energization. Here, we quantitatively demonstrate
for the first time how electromagnetic turbulence affects ion kinetics under
achievable laboratory conditions (millimeter-scale interpenetrating plasmas
with initial velocity of $2000\ \mathrm{km/s}$, density of $4 \times 10^{19}\
\mathrm{cm}^{-3}$, and temperature of $100\ \mathrm{eV}$) utilizing a recently
developed high-order implicit particle-in-cell code without scaling
transformation. It is found that the electromagnetic turbulence is driven by
ion two-stream and filamentation instabilities. For the magnetized scenarios
where an applied magnetic field of tens of Tesla is perpendicular to plasma
flows, the growth rates of instabilities increase with the strengthening of
applied magnetic field, which therefore leads to a significant enhancement of
turbulence fields. Under the competition between the stochastic acceleration
due to electromagnetic turbulence and collisional thermalization, ion
distribution function shows a distinct super-Gaussian shape, and the ion
kinetics are manifested in neutron yields and spectra. Our results have well
explained the recent unmagnetized experimental observations, and the findings
of magnetized scenario can be verified by current astrophysical experiments.
