At the Earth's orbit

PHYSICS · Subjective · Fermi University Physics · Earth, Climate & Energy Physics · Energy resources and conversion · Energy resources and conversion

Energy from Physics, Ch The solar resource resolved: geometry, spectrum and the limits of concentration

Problem

At the Earth's orbit, the diluted

5772\,\mathrm{K}

blackbody Sun delivers a photon flux above

1.12\,\mathrm{eV}

\Phi = 3.3\times10^{21}\,\mathrm{m^{-2}\,s^{-1}}

, equivalent to a current density of

53\,\mathrm{mA\,cm^{-2}}

if every photon above this energy freed one electron. Mercury orbits at

d_{\rm Me} = 0.387

times the Earth-Sun distance. Using the fact that moving to a different distance only rescales the solar dilution factor

f_\odot = (R_\odot/d)^2

and leaves the spectral shape unchanged, calculate the photon flux above

1.12\,\mathrm{eV}

and the equivalent current density at Mercury's orbit.