The Kelvin–Helmholtz (KH) instability is one of the most important mechanisms of the viscous like interaction between the solar wind and the magnetosphere (MSP), which transport the mass, energy, momentum, and magnetic flux. Thus, it is important to examine whether the magnetopause boundary is KH unstable or not. Based on the KH onset conditions, this report proposes to use a matrix to identify the most KH unstable direction based on the in-situ measurements of the density, velocity, and magnetic field in the MSP and magneto sheath. The range of the KH unstable direction can be easily estimated based on the eigenvalues of the matrix. The eigenvectors of the matrix provide a new boundary normal coordinate system, which could be useful for 2-D KH instability simulation.
JGR Space Physics
AGU Advancing Earth and Space Sciences
Grant or Award Name
NASA funding: 80NSSC18K1108, 80NSSC22K0304, 80NSSC18K1381, DOE funding: GC87041, and NSF funding: 2308853
Scholarly Commons Citation
Ma, X. (2023). Estimation of the Kelvin–Helmholtz unstable boundary. Journal of Geophysical Research: Space Physics, 128, e2023JA031602. https://doi. org/10.1029/2023JA031602