Extended Data Fig. 7: Wave activity in a 1D local shock simulation with Alfvén Mach number MA = 4.
From: Transmission of foreshock waves through Earth’s bow shock
Proton density (a), magnetic field strength (b) and magnetic field components (c) along the x axis at t = 500 s from the beginning of the simulation. (d) and (e) Dispersion plots obtained from the 2D Fourier transform of the magnetic field strength (d) and By component (e) between x = -10 RE and x = -5 RE (marked by the black bar in panel (b)) and t = 250 - 500 s, using unfiltered data to which a Hann window has been applied along both dimensions. On the horizontal axis, the frequencies are normalised to the ion cyclotron frequency Ωci and the wave number, on the vertical axis, to the proton inertial length dp. The solid yellow lines show the Courant-Friedrichs-Lewy condition, which is the maximum speed at which information can travel in the simulation, the blue dash-dotted lines the median Alfvén speed, and the pink line the median fast-magnetosonic speed in the magnetosheath at the locations used to calculate the 2D Fourier transform. The median bulk speed is indicated by the green dashed line.
