Magnetic flux in the internetwork quiet Sun

We report a direct comparison of the amplitudes of Stokes spectra of the Fe I 630 nm and 1.56 μm lines produced by realistic MHD simulations with simultaneous observations in the same spectral regions. The Stokes spectra were synthesized in snapshots with a mixed polarity magnetic field having a spatially averaged strength, 〈B〉, between 10 and 30 G. The distribution of Stokes V amplitudes depends sensitively on 〈B〉. A quiet inter-network region was observed at the German VTT simultaneously with TIP (1.56 μm) and POLIS (630 nm). We find that the Stokes V amplitudes of both infrared and visible observations are best reproduced by the simulation snapshot with 〈B〉 = 20 C. In observations with 1" resolution, up to 2/3 of the magnetic flux can remain undetected.