Widespread applicability of SGT

• We developed a theory based on SGT for low frequency waves near the ion cyclotron frequency that should be driven by interstellar pickup ions beyond about 1 AU [Zank and Cairns, 2000, 2001]. The theory predicts that the waves should be bursty, irregular, and very hard to detect, not inconsistent with observational failures to date.
• We demonstrated that bursty waves near the plasma frequency over Earth's polar cap (so-called PF waves) have field statistics consistent with SGT [Cairns and Menietti, 2001]. We also developed a theoretical model for why SGT applies that appears consistent with the observations to date and inferred the presence of slow electron beams in this region.
• We demonstrated that electromagnetic ion cyclotron (EMIC) and mirror mode waves in Earth's magnetosheath have field statistics consistent with SGT [Cairns and Grubits, 2001]. This represents a major test of SGT, since the waves were known independently to be near marginal stability (as expected for SGT states), and a major generalization in applicability since these waves are electromagnetic, are driven by an ion temperature anisotropy instability, and are in ``ion'' rather than ``electron'' modes.
• We showed that the well-known variability of the Vela pulsar, both from pulse to pulse at a given phase and also from phase to phase in a given pulse, corresponds to lognormal statistics, and so to consistency with pure SGT [Cairns et al., 2001; Cairns and Robinson, 2002]. The field statistics show no evidence for nonlinear processes, thereby ruling out nonlinear processes for the Vela pulsar. This extends SGT's applicability to pulsars, the archetypal astrophysical example of coherent emissions, and also to freely propagating electromagnetic radiation.
• This research shows that SGT is widely applicable in space plasmas and some astrophysical plasmas, applying in all 9 cases yet considered [Cairns et al., 2000a; Robinson and Cairns, 2001].

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