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How does gravity confine the fusion plasma inside stars?
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nuclear fusion
Interior of the U.S. Department of Energy's National Ignition Facility (NIF), located at Lawrence Livermore National Laboratory, Livermore, California. The NIF target chamber uses a high-energy laser to heat fusion fuel to temperatures sufficient for thermonuclear ignition. The facility is used for basic science, fusion energy research, and nuclear weapons testing.
In stars, the fusion plasma is confined by the immense gravitational field generated by the star's own mass. This gravitational force exerts an inward pressure that acts to compress the stellar material.123
This inward gravitational pressure is balanced by the outward pressure exerted by the hot plasma in the star's core. This state of balance, where the inward pull of gravity is countered by the outward pressure of the gas, is known as hydrostatic equilibrium. As long as this equilibrium is maintained, the star remains stable, allowing the nuclear fusion reactions to continue as the primary energy source.342