  Solar flares and coronal mass ejections, the primary space weather
disturbances affecting the entire heliosphere and near-Earth environment,
mainly emanate from sunspot regions harbouring high degrees of magnetic twist.
However, it is not clear how magnetic helicity, the quantity for measuring the
magnetic twist, is supplied to the upper solar atmosphere via the emergence of
magnetic flux from the turbulent convection zone. Here, we report
state-of-the-art numerical simulations of magnetic flux emergence from the deep
convection zone. By controlling the twist of emerging flux, we find that with
the support of convective upflow, the untwisted emerging flux can reach the
solar surface without collapsing, in contrast to previous theoretical
predictions, and eventually create sunspots. Because of the turbulent twisting
of magnetic flux, the produced sunspots exhibit rotation and inject magnetic
helicity into the upper atmosphere, amounting to a substantial fraction of
injected helicity in the twisted cases that is sufficient to produce flare
eruptions. This result indicates that the turbulent convection is responsible
for supplying a non-negligible amount of magnetic helicity and potentially
contributes to solar flares.
