PLASMA In the literature: contested

Electron thermal and electrical conductivity of warm dense matter

In plain words

How fast heat flows through warm dense matter controls how a fusion capsule's shell burns away and how fast its hot core cools. Different theories disagree by large factors, and almost no measurements exist.

Precise statement

For hydrogen, carbon and CH at density 1 to 100 $\mathrm{g}/\mathrm{cm}^3$ and temperature 10 to 300 eV (ion coupling and electron degeneracy both of order 1), determine the electrical conductivity $\sigma$ and electron thermal conductivity $\kappa$, and the Lorenz number $L=\kappa e^2/(\sigma T)$ ($T$ in energy units) relative to the degenerate value $\pi^2/3$; Kubo-Greenwood DFT-MD, time-dependent DFT, average-atom and Lee-More type models differ by factors of up to several. An answer is measured $\kappa$ and $\sigma$ with 20 percent precision at two or more conditions and a theory matching them.

What would settle it

Time-resolved conductivity measurements (e.g. X-ray or optical probes of isochorically heated or shocked samples) at 20 percent precision, compared with first-principles calculations.

Status in the literature

A code-comparison workshop (Grabowski et al. 2020, https://doi.org/10.1016/j.hedp.2020.100905) documented large spreads between transport models in this regime.

See also