We present a measurement of the spectral index of density fluctuations between ion and electron scales in solar wind turbulence using the EFI instrument on the ARTEMIS spacecraft .
The mean spectral index at 1 AU was found to be –2.75 \pm 0.06 , steeper than predictions for pure whistler or kinetic Alfvén wave turbulence , but consistent with previous magnetic field measurements .
The steep spectra are also consistent with expectations of increased intermittency or damping of some of the turbulent energy over this range of scales .
Neither the spectral index nor the flattening of the density spectra before ion scales were found to depend on the proximity to the pressure anisotropy instability thresholds , suggesting that they are features inherent to the turbulent cascade .