Triggering Higgs vacuum decay

The Standard Model Higgs potential seems unstable at field values $h > h_{\rm top} \sim 10^{10}\,{\rm GeV}$. Vacuum decay can be triggered by $N\sim 4\pi/\lambda \sim 1000$ overlapped Higgs bosons with energy $\sqrt{\lambda} h_{\rm top}$. However, this configuration is stimulated by ultra-high energy collisions with a $\exp(-{\cal O}(N))$ suppression, comparable to spontaneous vacuum decay: no `Higgspolosion' enhancement arises. This implies that ultra-high energy cosmic ray collisions are safe, despite that their number (in production sites) likely is tens of orders of magnitude higher than what usually estimated (in space). We speculate on how vacuum decay could be induced classically, forming a in-coming wave of $N$ boosted Higgs bosons at futuristic ultra-high energy colliders, and on how the resulting vacuum bubble could be controlled to extract energy.