TY - GEN
T1 - The effect of magnetic turbulence energy spectra and pickup ions on the heating of the solar wind
AU - Ng, C. S.
AU - Bhattacharjee, A.
AU - Isenberg, P. A.
AU - Munsi, D.
AU - Smith, C. W.
PY - 2010
Y1 - 2010
N2 - In recent years, a phenomenological solar wind heating model based on a turbulent energy cascade prescribed by the Kolmogorov theory has produced reasonably good agreement with observations on proton temperatures out to distances around 70 AU, provided the effect of turbulence generation due to pickup ions is included in the model. In a recent study [Ng et al., J. Geophys. Res., 115, A02101 (2010)], we have incorporated in the heating model the energy cascade rate based on Iroshnikov-Kraichnan (IK) scaling, derivable from incompressible magnetohydrodynamics. We showed that the IK cascade rate can also produce good agreement with observations, with or without the inclusion of pickup ions. This effect was confirmed both by integrating the model using average boundary conditions at 1 AU, and by applying a method [Smith et al., Astrophys. J., 638, 508 (2006)] that uses directly observed values as boundary conditions. The reduction of effects due to pickup ions is because less turbulence is generated by pickup ions for the IK spectrum, which has a shallower spectral index than the Kolmogorov spectrum. In this paper, we will discuss more on this part of the theory.
AB - In recent years, a phenomenological solar wind heating model based on a turbulent energy cascade prescribed by the Kolmogorov theory has produced reasonably good agreement with observations on proton temperatures out to distances around 70 AU, provided the effect of turbulence generation due to pickup ions is included in the model. In a recent study [Ng et al., J. Geophys. Res., 115, A02101 (2010)], we have incorporated in the heating model the energy cascade rate based on Iroshnikov-Kraichnan (IK) scaling, derivable from incompressible magnetohydrodynamics. We showed that the IK cascade rate can also produce good agreement with observations, with or without the inclusion of pickup ions. This effect was confirmed both by integrating the model using average boundary conditions at 1 AU, and by applying a method [Smith et al., Astrophys. J., 638, 508 (2006)] that uses directly observed values as boundary conditions. The reduction of effects due to pickup ions is because less turbulence is generated by pickup ions for the IK spectrum, which has a shallower spectral index than the Kolmogorov spectrum. In this paper, we will discuss more on this part of the theory.
KW - MHD turbulence
KW - Pickup ions
KW - Solar wind heating
KW - Wave-particle interaction
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U2 - 10.1063/1.3529966
DO - 10.1063/1.3529966
M3 - Conference contribution
AN - SCOPUS:79251538639
SN - 9780735408579
T3 - AIP Conference Proceedings
SP - 174
EP - 179
BT - Pickup Ions Throughout the Heliosphere and Beyond - Proceedings of the 9th Annual International Astrophysics Conference
T2 - 9th Annual International Astrophysics Conference on Pickup Ions Throughout the Heliosphere and Beyond: Dedicated to the Memory of Sir W. Ian Axford January 2, 1933 - March 13, 2010
Y2 - 14 March 2010 through 19 March 2010
ER -