Evaluation -- The AZD2014 Positive Aspects And also Negatives
Fewer computations have displayed OPHN1 the temporal evolution of the fluctuating magnetic field spectra in both k�� and k�� [60]. Hellinger et al. [61] used in-plane 2D PIC hybrid simulations and Shoji et al. [62] used both 2D and 3D PIC simulations to examine the competition between these two ion-anisotropy-driven instabilities. Shoji et al. [62] showed that, for both the Alfv��n-cyclotron and the mirror instabilities, nonlinear post-saturation effects shift the enhanced fluctuations to longer wavelengths. But neither paper shows evidence for the development of broadband, turbulent-like spectra. (c) Interpretations and questions (1)?The gyrokinetic simulations of Alfv��nic and kinetic Alfv��n turbulence exclude magnetosonic-whistler fluctuations. However, hybrid and full PIC simulations can represent both incompressive and compressive modes. Such simulations should be used to address the following questions: Can Alfv��nic turbulence at short wavelengths couple to magnetosonic-whistler selleck chemical turbulence? Can these compressive modes play a significant role in very short wavelength turbulence of the electron-scale domain? (2)?The short-wavelength Alfv��nic turbulence results from the Vlasov simulation results of Valentini et al. [51] yield a quasi-parallel wavevector anisotropy for sufficiently large Te/Ti, whereas the 2D hybrid simulations of Verscharen et al. [52] and Comi?el et al. [53] at large Te/Ti produce the opposite, characteristic k��?k�� anisotropy. What is the resolution of this apparent contradiction? (3)?Can the Alfv��n-cyclotron anisotropy instability enhance turbulent fluctuation spectra at short wavelengths? It is unlikely that inverse cascades from this instability would add appreciable energy to the relatively large amplitude turbulence of the inertial range, but it is possible that forward cascades from this growing mode could contribute to the physics of the short-wavelength regime. (4)?Wu et al. [63] carried out 2D PIC simulations with Bo out of the simulation FRAX597 supplier plane, studying the decay of long-wavelength ��Alfv��n mode�� turbulence as it cascades to kinetic ion-scale lengths. At small initial amplitudes, the turbulence heats electrons primarily, but stronger turbulence leads to the domination of proton heating. This is a very interesting result which deserves further study, and particularly in 3D configurations which will allow the full consequences of Landau and cyclotron damping to become manifest. (5)?Why does the linear theory threshold of the proton mirror instability provide a better fit as a constraint to observed proton anisotropies than does the threshold of the Alfv��n-cyclotron instability [64,65]? 5.?Magnetosonic turbulence and T��i
