# An advanced three-axis elliptical hohlraum for indirectly driven inertial confinement fusion

## TL;DR

This paper proposes an advanced three-axis elliptical hohlraum (TAEH) that balances radiation symmetry, plasma filling time, and coupling efficiency, offering a promising alternative for indirect-drive inertial confinement fusion ignition.

## Contribution

The introduction of the TAEH design demonstrates improved performance metrics over existing hohlraum configurations through preliminary simulations.

## Key findings

- TAEH provides excellent radiation symmetry comparable to SH and TACH.
- Plasma filling time of TAEH is between SH and TACH, close to NVCH.
- Coupling efficiency of TAEH is significantly higher than NVCH, SH, and TACH.

## Abstract

The radiation symmetry and laser-plasma instabilities (LPIs) inside the conventional cylindrical hohlraum configuration are the two daunting challenges on the approach to ignition in indirectly driven inertial confinement fusion. Recently, near-vacuum cylindrical hohlraum (NVCH), octahedral spherical hohlraum (SH) and novel three-axis cylindrical hohlraum (TACH) were proposed to mitigate these issues. While the coupling efficiency might still be a critical risk. In this paper, an advanced three-axis elliptical hohlraum (TAEH) is proposed to make a compromise among these hohlraum performance. Preliminary simulations indicate that the TAEH (with a case-to-capsule ratio, CCR=2.8) could provide excellent radiation symmetry during the thorough laser pulse of the high-foot drive, comparable to the ones inside the SH (CCR=5.1) and TACH (CCR=2.2). The filling time of plasma affecting the LPIs is between those of SH and TACH, and about 1.5 times of that in the ignition hohlraum Rev5-CH of NIC and close to the one inside the NVCH (CCR=3.4). In particular, the coupling efficiency is about 22%, 29% and 17% higher than the one inside the NVCH, SH and TACH, respectively. It would be envisioned that the proposed hohlraum configuration merits consideration as an alternative route to indirect-drive ignition, complementary to the traditional cylindrical hohlraum and the proposed recently novel hohlraums.

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Source: https://tomesphere.com/paper/1703.01579