  We report the experimental results of the commissioning phase in the 10 PW
laser beamline of Shanghai Superintense Ultrafast Laser Facility (SULF). The
peak power reaches 2.4 PW on target without the last amplifying during the
experiment. The laser energy of 72\pm 9 J is directed to a focal spot of ~6
{\mu}m diameter (FWHM) in 30 fs pulse duration, yielding a focused peak
intensity around 2.0 \times 10^{21} W/cm^2. First laser-proton acceleration
experiment is performed using plain copper and plastic targets. High-energy
proton beams with maximum cut-off energy up to 62.5 MeV are achieved using
copper foils at the optimum target thickness of 4 {\mu}m via target normal
sheath acceleration (TNSA). For plastic targets of tens of nanometers thick,
the proton cut-off energy is approximately 20 MeV, showing ring-like or
filamented density distributions. These experimental results reflect the
capabilities of the SULF-10 PW beamline, e.g., both ultrahigh intensity and
relatively good beam contrast. Further optimization for these key parameters is
underway, where peak laser intensities of 10^{22}-10^{23} W/cm^2 are
anticipated to support various experiments on extreme field physics.
