[FredZarguna]

You are mistaken. The solar core, clearly, is at ignition temperature. The fact that energy production / unit time is low has nothing to do with whether ignition has occurred. Had it not, we would not be having this conversation.

Massive stars that can undergo pair production instability are not using fusion mechanisms that are envisaged in the ICF. These stars, I believe, are triple-alpha-cycle degenerating stars. At the very least they are carbon-cycle stars. Their energy is not coming from the fusion of isotopes of hydrogen.

[dr_lew]

The collapse proceeds to efficiently compress the star's core; the overpressure is sufficient to allow runaway nuclear fusion to burn it in a few seconds, creating a thermonuclear explosion.[6]

6: Fryer, C.L.; Woosley, S. E.; Heger, A. (2001). "Pair-Instability Supernovae, Gravity Waves, and Gamma-Ray Transients". The Astrophysical Journal 550 (1). arXiv:astro-ph/0007176. Bibcode:2001ApJ...550..372F. doi:10.1086/319719