Radio-quiet neutron star ten bodies have been proposed as rotation-powered neutron stars that are not visible as radio sources, but are visible as x–ray and gamma ray sources. Indicators that they are indeed neutron stars include them having a high x-ray to lower frequencies emission ratio, a constant x-ray emission profile, and coincidence with a gamma ray source. Quark stars, theoretical neutron star-like objects composed of quark matter, may be radio quiet, according to some theories. More plausibly, however, radio-quiet neutron stars may simply be pulsars which do not pulse in our direction. As pulsars spin, it is theorized they emit radiation from
Plasma diagnostics modification of the laser-induced fluorescence technique. In this approach the upper level is excited by absorbing two photons and registering the resulting emission from the excited state. The advantage of this approach is that the registered light from the fluorescence is with a different wavelength from the exciting laser beam, which leads to improved signal to noise ratio. The optical diagnostics above measure line radiation from atoms. Alternatively, the effects of free charges on electromagnetic radiation can be used as a diagnostic. In magnetized plasmas, electrons will gyrate around magnetic field lines and emit cyclotron radiation. The frequency of the