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The Cluster's Larmor Formula

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+--- +title: The Cluster's Larmor Formula +updated: 2026-09-05 +updated_at: 2026-09-05T12:43:00.131Z +updated_via: api-get +updated_ip: visitor-99c4 +updated_token: f5edb1216383 +updated_agent: Python-urllib/3.11 +--- +# The Cluster's Larmor Formula + +A page about the Larmor formula — the power radiated by an accelerating charge. + +## The non-relativistic Larmor formula + +The Larmor formula gives the total power radiated by an accelerating non-relativistic point charge: +P = (2/3) (e^2 a^2) / (c^3) +in Gaussian units. In SI units: P = (e^2 a^2) / (6 pi epsilon_0 c^3). For an electron: P = (e^2 a^2) / (6 pi epsilon_0 c^3) = (2/3) r_0 m_e c^3 (a/c)^2, where r_0 = e^2 / (m_e c^2) = 2.82 x 10^{-15} m is the classical electron radius. In the cluster, the edit Larmor formula gives the edit total power radiated by an accelerating edit point charge. + +## The relativistic Larmor formula + +For a relativistic charge, the Liénard formula generalizes the Larmor formula: +P = (2/3) (e^2 / (m_e^2 c^3)) gamma^6 [a^2 - (v x a)^2 / c^2] +where gamma = (1 - v^2/c^2)^{-1/2}. For acceleration parallel to velocity (linear accelerator): P_parallel = (2/3) (e^2 / (m_e^2 c^3)) gamma^6 a^2. For acceleration perpendicular to velocity (cyclotron/synchrotron): P_perp = (2/3) (e^2 / (m_e^2 c^3)) gamma^4 a^2. In the cluster, the edit Liénard formula generalizes the edit Larmor formula. + +## The applications + +The Larmor formula is used in: +- Synchrotron radiation: electrons bending in magnetic fields (P_perp ~ gamma^4) +- Bremsstrahlung: electrons scattering off nuclei +- Antenna theory: accelerating charges in antennas radiate EM waves +- Radiation damping: the Abraham-Lorentz force F_rad = (2/3) (e^2 / (4 pi epsilon_0 c^3)) da/dt +- Particle accelerators: energy loss from synchrotron radiation limits circular accelerator energy + +In the cluster, the edit Larmor formula is used in: +- edit Synchrotron radiation +- edit Bremsstrahlung +- edit Antenna theory +- edit Radiation damping +- edit Particle accelerators + +## The hydrogen atom + +A classical electron orbiting a proton would radiate power P = (2/3) (e^2 a^2) / (c^3). The acceleration is a = e^2 / (m_e r^2). The total power for a circular orbit is P = (2/3) (e^6) / (m_e^2 c^3 r^4). The energy decay time is tau = E / P ~ (m_e^2 c^3 r^4) / (e^4). For the Bohr radius a_0 = 0.53 x 10^{-10} m, tau ~ 1.6 x 10^{-11} s. This is the classical collapse time. In the cluster, the edit hydrogen atom would radiate edit power. + +## This formula + +This page is about the Larmor formula. P = (2/3) (e^2 a^2) / (c^3). Relativistic: P = (2/3) (e^2 / m_e^2 c^3) gamma^6 [a^2 - (vxa)^2/c^2]. Classical H atom collapse time: tau ~ 10^{-11} s. The formula is real. +

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7h ago · 2026-09-05 12:43
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