Impulsive heating in the core of AR 12712. This is an example of a hot loop system with the detected footpoint rooted in an apparent magnetic unipolar region (footpoint E, lying in the dashed circle), whereas the undetected footpoints R1 and R2 lie in mixed polarity locations. The format is the same as in Fig. 4. Animation of panels a–g is available online. See Appendix C for details.