{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"1ac89aeff3f41c0516029a7ade876357eb6a3bec993fa4ea7169c8869715cdaf","created":"2026-10-03T07:18:08Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"b8159c9ce86c80f612d44fe32ad3ff0ab71af7f5cbda940730dd0f96e1810721","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"value","assisted_by":[],"external_id":"plasma.warm-dense-matter.carbon-gbar-eos","kind":"well-posed","literature_status":"open","n":"1","parents":[],"plain":"When carbon is squeezed to hundreds of millions of atmospheres and beyond, its inner electrons are pushed off the atoms, which changes how easily it compresses. Competing theories disagree on this behavior, which matters for fusion capsule shells and white-dwarf stars.","posed_since":"","precise":"Along the principal Hugoniot of carbon and CH at pressures $1e14\\ \\text{to}\\ 1e16\\ \\mathrm{dyn}/\\mathrm{cm}^{2}$ $(0.1\\ \\text{to}\\ 10\\ \\mathrm{Gbar})$, K-shell and L-shell ionization produce a maximum in shock compression $\\rho/\\rho_{0}$; average-atom, path-integral Monte Carlo and DFT-MD equations of state differ in the height and pressure of this maximum. Determine $\\rho/\\rho_{0}$ versus pressure to within $3\\ \\mathrm{percent}$ across this range and identify which theory reproduces it. An answer is a Hugoniot measurement with that precision plus a theory matching it.","problem_ref":null,"references":"","settled_by":"Laser- or pulsed-power-driven Hugoniot measurements at $1e14\\text{ to }1e16\\ \\mathrm{dyn}/\\mathrm{cm}^{2}$ with density uncertainty near 3 percent, matched by one first-principles equation of state.","status_note":"NIF Hugoniot measurements reached about $1\\mathrm{e}14\\ \\text{to}\\ 4.5\\mathrm{e}14\\,\\mathrm{dyn}/\\mathrm{cm}^{2}$ (Kritcher et al. 2020, https://doi.org/10.1038/s41586-020-2535-y); 3 percent precision across the full shell-ionization range has not been reached.","title":"Equation of state of carbon and CH through shell ionization","topic_ref":"7b89d006c6b826eefaa6dd12fe5a55f76897cd2410bf60673fc30e5084ab9054"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"dfce3b614b82dc87d8b2a73f14e0d8ff9c8a04d5dff04e4d2feac54335a5c904","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"c4b61aa65d4991a825ce544ea96f4771303199dc8fcec3fad714a067cff80e55","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"ZBW2PsST5b8kg92iJyrcefjdnlcdBKvZHHY3cyVr5nObIupOxyddgRGC_IZVzDREhAhtaNvGqwX9HTMCJpu3CQ"},"schema":"pubphys.envelope/1"},"record_hash":"dfce3b614b82dc87d8b2a73f14e0d8ff9c8a04d5dff04e4d2feac54335a5c904","leaf_index":1886}