We report on measurement techniques of the charge, spectrum, divergence, transverse emittance and the first real-time
observation of the accelerated electron pulse and the accelerating plasma wave. Our time-resolved study allows a singleshot
measurement of the electron bunch duration providing a value of 5.8 +1.9 -2.1 fs full-width at half maximum
(2.5+0.8 -0.9 fs root mean square) as well as the plasma wave with a density-dependent period of 12-22 fs. It reveals the
evolution of the bunch, its position in the surrounding plasma wave and the wake dynamics. The results afford promise
for brilliant, sub-angstrom-wavelength ultrafast electron and photon sources for diffraction imaging with atomic
resolution in space and time.
Recent years have seen rapid improvement in the quality of electron beams produced by wakefields in plasmas.
The electron beams produced have inherently short durations and high peak current. To further shorten the pulse
duration of these beams for future applications, an experiment is proposed to produce a single sub-femtosecond
slice of electrons via an Inverse Free Electron Laser interaction (IFEL) with a few cycle laser pulse. The IFEL
is followed by a combined function, permanent magnet quadrupole triplet chicane that both disperses the beam
transversely while simultaneously focusing, allowing for efficient energy collimation to select the attosecond slice.
Simulations are presented showing the expected electron slice characteristics.