We have searched for a flux of axions produced in the Sun by exploiting their conversion to x rays in a static magnetic field. The signature of a solar axion flux would be an increase in the rate of x rays detected in a magnetic telescope when the Sun passes within its acceptance. From the absence of such a signal we set a 3σ limit on the axion coupling to two photons ${\mathit{g}}_{\mathit{a}\gamma \gamma }$≡1/M<3.6×${10}^{\mathrm{-}9}$ ${\mathrm{GeV}}^{\mathrm{-}1}$, provided the axion mass ${\mathit{m}}_{\mathit{a}}$<0.03 eV and <7.7×${10}^{\mathrm{-}9}$ ${\mathrm{GeV}}^{\mathrm{-}1}$ for 0.03 <${\mathit{m}}_{\mathit{a}}$<0.11 eV.

• Received 22 May 1992

DOI:https://doi.org/10.1103/PhysRevLett.69.2333