The basic scales of motion and computational requirements for low frequency fluid drift turbulence are summarised in tutorial fashion. Basic signatures for each of the competing eigenmode types are given, some of which are accessible experimentally. The emphasis is on edge turbulence since it is less intuitive. The difference in physical mechanism between linear instabilities and fully developed turbulence at the same parameters is shown. The difference in physical character from more familiar

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... HD models is also addressed. Experimentally, one needs to measure the fluctuating potential as well as the transported quantities in order to distinguish among physical mechanisms.