Interface Thermal Resistance Confirmed in High-Energy-Density Matter: Implications for Fusion

Researchers have confirmed the existence of Interface Thermal Resistance (ITR) in high-energy-density (HED) matter, a finding that could significantly impact inertial confinement fusion research. The experiment, conducted at the OMEGA 60 laser facility, involved heating a plastic-coated tungsten wire with X-rays to create a high-energy-density interface. Using Fresnel diffractive radiography, scientists observed a temperature discontinuity of approximately 6 eV at the interface, demonstrating restricted heat flow and substantial ITR. The measured interfacial thermal resistance was R = 3.7 × 10⁻¹⁰ ± 8 × 10⁻¹¹ m²K/W. This discovery challenges the assumption that abundant conducting electrons eliminate ITR in HED environments. The presence of ITR can affect temperature measurements in dynamic compression experiments and significantly impact the design of fuel-containing capsules in inertial confinement fusion, where temperature discontinuities at material interfaces can lead to pressure gradients and affect hydrodynamic instability growth. Incorporating ITR considerations into fusion target designs may improve predictive capabilities and advance inertial fusion energy concepts.