  Compact acceleration of a tightly collimated relativistic electron beam with
high charge from a laser-plasma interaction has many unique applications.
However, currently the well-known schemes, including laser wakefield
acceleration from gases and vacuum laser acceleration from solids, often
produce electron beams either with low charge or with large divergence angles.
In this work, we report the generation of highly collimated electron beams with
a divergence angle of a few degrees, quasi-monoenergetic spectra peaked at the
MeV level, and extremely high charge ($\sim$100 nC) via a powerful sub-ps laser
pulse interacting with a solid target in grazing incidence. Particle-in-cell
simulations illustrate a new direct laser acceleration scenario, in which the
self-filamentation is triggered in a large-scale near-critical-density plasma
and electron bunches are accelerated periodically and collimated by the
ultra-intense electromagnetic field. The energy density of such electron beams
in high-Z materials reaches to $\sim10^{12} \mathrm{J/m^{3}}$, making it a
promising tool to drive warm or even hot dense matter states.
