  It has been observationally well established that the magnetic configurations
most favorable for producing energetic flaring events reside in delta-spots, a
class of sunspots defined as having opposite polarity umbrae sharing a common
penumbra. They are frequently characterized by extreme compactness, strong
rotation and anti-Hale orientation. Numerous studies have shown that nearly all
of the largest solar flares originate in delta-spots, making the understanding
of these structures a fundamental step in predicting space weather. Despite
their important influence on the space environment, surprisingly little is
understood about the origin and behavior of delta-spots. In this paper, we
perform a systematic study of the behavior of emerging flux ropes to test a
theoretical model for the formation of delta-spots: the kink instability of
emerging flux ropes. We simulated the emergence of highly twisted,
kink-unstable flux ropes from the convection zone into the corona, and compared
their photospheric properties to those of emerged weakly twisted, kink-stable
flux ropes. We show that the photospheric manifestations of the emergence of
highly twisted flux ropes closely match the observed properties of delta-spots,
and we discuss the resulting implications for observations. Our results
strongly support and extend previous theoretical work that suggested that the
kink instability of emerging flux ropes is a promising candidate to explain
delta-spot formation, as it reproduces their key characteristics very well.
