Chapter 2: A Review of the Possible Role of Constraints in MHD Turbulence

The following sections are included:

• Introduction

  • The context

  • The Kolmogorov law

  • The equations

• What can we learn from statistical mechanics

• Energy spectra

  • Weak MHD turbulence

  • When the weak regime breaks down

  • Intermittency

• Exact laws

• Explicit examples of non-universal behavior in MHD

• The role of alignment between the velocity and the magnetic field

• Can the dynamics of magnetic helicity play a role for energy scaling?

• Can models help?

• Conclusions

• Acknowledgments

• References