FIGURE 1. Laboratory measurement of magnetic fields greater than 340 megagauss.
From the following article:
Laser technology: Measuring huge magnetic fields
M. Tatarakis, I. Watts, F. N. Beg, E. L. Clark, A. E. Dangor, A. Gopal, M. G. Haines, P. A. Norreys, U. Wagner, M.-S. Wei, M. Zepf and K. Krushelnick
Nature 415, 280(17 January 2002)
doi:10.1038/415280a
a, Plot of x-wave cut-offs for various harmonics (second, third, and so on) of 1.054-
m radiation in terms of plasma electron density and magnetic field. b,X-wave/total harmonic emission of third harmonic (hollow circles) and fourth harmonic (filled circles) for a series of laser shots.