Inductive and space charge electric fields in a whistler wave packet

A low-frequency whistler wave packet is excited with a pulsed magnetic loop antenna in a large laboratory plasma (1 m diam×2.5 m, ${\mathit{n}}_{\mathit{e}}$=7×${10}^{11}$ ${\mathrm{cm}}^{\mathrm{-}3}$, ${\mathrm{kT}}_{\mathrm{e}}$=1.3 eV, ${\mathit{B}}_0$=20 G). Multipoint (${10}^4$) measurements of the wave magnetic field, B(r,t), and 4D fast Fourier transformation, B(k,ω), both verify the dispersion of oblique plane whistler modes and permit the calculation of the wave electric field, decomposed into its rotational (inductive) and irrotational (space charge) contributions, E(r,t)=${\mathbf{E}}_{\mathrm{ind}}$+${\mathbf{E}}_{\mathrm{sc}}$. The space charge density, ρ(r,t), for a whistler wave is also shown.