Editing Inertial confinement fusion (section)

===Early research===
Through the late 1950s,   and collaborators at [[Lawrence Livermore National Laboratory]] (LLNL) completed computer simulations of the ICF concept. In early 1960, they performed a full simulation of the implosion of 1&nbsp;mg of D-T fuel inside a dense shell. The simulation suggested that a 5 MJ power input to the hohlraum would produce 50 MJ of fusion output, a gain of 10x. This was before the laser and a variety of other possible drivers were considered, including pulsed power machines, charged particle accelerators, plasma guns, and [[hypervelocity]] pellet guns.{{sfn|Nuckolls|1998|p=4}}

Two theoretical advances advanced the field. One came from new simulations that considered the timing of the energy delivered in the pulse, known as "pulse shaping", leading to better implosion. The second was to make the shell much larger and thinner, forming a thin shell as opposed to an almost solid ball. These two changes dramatically increased implosion efficiency and thereby greatly lowered the required compression energy. Using these improvements, it was calculated that a driver of about 1 MJ would be needed,{{sfn|Nuckolls|1998|p=5}} a five-fold reduction. Over the next two years, other theoretical advancements were proposed, notably [[Ray Kidder]]'s development of an implosion system without a hohlraum, the so-called "direct drive" approach, and [[Stirling Colgate]] and Ron Zabawski's work on systems with as little as 1 μg of D-T fuel.{{sfn|Nuckolls|1998|pp=4-5}}

The introduction of the laser in 1960 at [[HRL Laboratories|Hughes Research Laboratories]] in California appeared to present a perfect driver mechanism. However, the maximum power produced by these devices appeared very limited, far below what would be needed. This was addressed with [[Gordon Gould]]'s introduction of the [[Q-switching]] which was applied to lasers in 1961 at [[Hughes Research Laboratories]]. Q-switching allows a laser amplifier to be pumped to very high energies without starting [[stimulated emission]], and then triggered to release this energy in a burst by introducing a tiny seed signal. With this technique it appeared any limits to laser power were well into the region that would be useful for ICF.<ref>{{cite journal |first=Thomas |last=Mahlhorn |title=From KMS Fusion to HB11 Energy and Xcimer Energy, a personal 50 year IFE perspective |journal=Physics of Plasmas |date=28 February 2024 |volume=31 |issue=2 |doi=10.1063/5.0170661 |url=https://pubs.aip.org/aip/pop/article/31/2/020602/3267722/From-KMS-Fusion-to-HB11-Energy-and-Xcimer-Energy-a|doi-access=free }}</ref>

Starting in 1962,{{efn|Mahlhorn says 1963.}} Livermore's director [[John S. Foster, Jr.]] and [[Edward Teller]] began a small ICF laser study. Even at this early stage the suitability of ICF for weapons research was well understood and was the primary reason for its funding.{{sfn|Nuckolls|1998|p=6}} Over the next decade, LLNL made small experimental devices for basic laser-plasma interaction studies.