Proton Heating by Nonlinear Field-Aligned Alfvén Waves in Solar Coronal Holes

Details Proton Heating by Nonlinear Field-Aligned Alfvén Waves in Solar Coronal Holes Proton Heating by Nonlinear Field-Aligned Alfvén Waves in Solar Coronal Holes

Apr 2009

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009apj...695.1413m&link_type=abstract

The Astrophysical Journal, Volume 695, Issue 2, pp. 1413-1420 (2009).

Astronomy and Astrophysics

Astronomy

13

Instabilities, Solar Wind, Sun: Corona, Waves

Scientific paper

Field-aligned Alfvén waves are often viewed as a source of the proton heating that accelerates the fast solar wind. However, the energy that they can inject into the protons in the limit of cyclotron-resonant quasi-linear diffusion is insufficient to account for the observed acceleration. To test the validity of this limit in coronal holes, nonlinear Alfvén waves are modeled using a hybrid code. It is found that the nonlinearity is particularly strong when the intensity of antisunward-propagating waves is comparable to that of sunward waves. The sunward waves can be generated by the proton distribution as it evolves with the heliocentric distance. The ponderomotive force and beat interaction are identified as the most important nonlinear effects. The nonlinearity of the field-aligned Alfvén waves produces density fluctuations. In the simulations, the amplitude of the density fluctuations was kept within the observed constraints from the interplanetary scintillation measurements in the corona. In this case, the characteristic time of the proton heating is almost 2 orders of magnitude smaller than the solar wind expansion time. Therefore, it can contribute to the energization of the solar wind on the global scale. The nonlinear wave damping operating alone cannot be responsible for the energization because it only causes particle diffusion parallel to the magnetic field. However, it can relax the limitation on the perpendicular diffusion imposed by the cyclotron resonance condition. The nonlinear damping combined with the linear one can then inject the additional thermal energy needed to accelerate the solar wind.

Affiliated with

Also associated with

No associations

Rating

Proton Heating by Nonlinear Field-Aligned Alfvén Waves in Solar Coronal Holes does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Proton Heating by Nonlinear Field-Aligned Alfvén Waves in Solar Coronal Holes, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Proton Heating by Nonlinear Field-Aligned Alfvén Waves in Solar Coronal Holes will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1861436