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Published equation contexts

a≈γ2c2/ra \approx \gamma^2 c^2/r

Why this formula appears here

Electrons circulating in a storage ring undergo enormous proper acceleration — for an ultra-relativistic beam of Lorentz factor γ\gamma on a ring of radius r , the proper centripetal acceleration is a ≈\approx γ2\gamma^2 c2c^2/r . For beam parameters typical of a large electron-positron collider, with γ\gamma of order 2×\times10^5 and r of order several kilometers, this works out to a ∼\sim 8×\times10^{23}\,m s−2\mathrm{m\,s^{-2}} , corresponding by the Unruh formula to TUT_U = ℏ\hbar a/(2π\pi c kBk_B) ∼\sim 3×\times10^3\,K\mathrm K — a temperature scale that is, remarkably, not astronomically small, unlike the roughly 10^{-19}\,K\mathrm K an Earth-bound laboratory accelerometer would need a planet’s worth of…

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aa

Symbol a

a is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.

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γ2\gamma^2

Symbol gamma^2

gamma2a^2 is squared: multiply the underlying quantity by itself. The square is a mathematical operation, not a second independent variable.

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Its accuracy depends on the assumptions and range of use described in the article.

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Published contexts (1)

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a≈γ2c2/ra \approx \gamma^2 c^2/r

Equation 100 · Evolutionary Physics

No Particle Without a Cosigner

This equation gives an approximation: it relates the quantities while allowing an approximation.

Electrons circulating in a storage ring undergo enormous proper acceleration — for an ultra-relativistic beam of Lorentz factor γ\gamma on a ring of radius r , the proper centripetal acceleration is a ≈\approx γ2\gamma^2 c2c^2/r . For beam parameters typical of a large electron-positron collider, with γ\gamma of order 2×\times10^5 and r of order several kilometers, this works out to a ∼\sim 8×\times10^{23}\,m s−2\mathrm{m\,s^{-2}} , corresponding by the Unruh formula to TUT_U = ℏ\hbar a/(2π\pi c kBk_B) ∼\sim 3×\times10^3\,K\mathrm K — a temperature scale that is, remarkably, not astronomically small, unlike the roughly 10^{-19}\,K\mathrm K an Earth-bound laboratory accelerometer would need a planet’s worth of…

Meanings in this article

  • rr: the radius.
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