  Measuring the magnetic helicity distribution in the solar corona can help in
understanding the trigger of solar eruptive events because magnetic helicity is
believed to play a key role in solar activity due to its conservation property.
A new method for computing the photospheric distribution of the helicity flux
was recently developed. This method takes into account the magnetic field
connectivity whereas previous methods were based on photospheric signatures
only. This novel method maps the true injection of magnetic helicity in active
regions. We applied this method for the first time to an observed active
region, NOAA 11158, which was the source of intense flaring activity. We used
high-resolution vector magnetograms from the SDO/HMI instrument to compute the
photospheric flux transport velocities and to perform a nonlinear force-free
magnetic field extrapolation. We determined and compared the magnetic helicity
flux distribution using a purely photospheric as well as a connectivity-based
method. While the new connectivity-based method confirms the mixed pattern of
the helicity flux in NOAA 11158, it also reveals a different, and more correct,
distribution of the helicity injection. This distribution can be important for
explaining the likelihood of an eruption from the active region. The
connectivity-based approach is a robust method for computing the magnetic
helicity flux, which can be used to study the link between magnetic helicity
and eruptivity of observed active regions.
