I’m not a physicist, but if I wanted to fuse metallic hydrogen I’d think about a really direct approach: shooting two deuterium/tritium bullets at each other at 1.5% of c (for a Coulomb barrier of 0.1 MeV according to Wikipedia). The most questionable part I can see is that a nucleus from one bullet could be expected to miss thousands of nuclei from the other, before it hit one, and I would worry about losing too much energy to bremsstrahlung in those encounters.
I’m not a physicist, but if I wanted to fuse metallic hydrogen I’d think about a really direct approach: shooting two deuterium/tritium bullets at each other at 1.5% of c (for a Coulomb barrier of 0.1 MeV according to Wikipedia). The most questionable part I can see is that a nucleus from one bullet could be expected to miss thousands of nuclei from the other, before it hit one, and I would worry about losing too much energy to bremsstrahlung in those encounters.