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We present magnetic field, VLF electric field, and directed positive ion flux measurements made during passage of OGO 5 through many bow shock structures both inbound and outbound on March 12, 1968. These shocks were chosen because the period March 11–13, 1968, was one of a reasonably quiet solar wind. The data are correlated on time scales ≥144 msec and show that electrostatic wave turbulence is generated in the shock front by diamagnetic currents flowing on scale lengths ∼c/ωp−, the electron inertial length. This electrostatic turbulence builds to high levels near or in the regions of large jumps in |B| and then decays rapidly downstream. A jump in |B| and the scattering or randomization of protons are observed to occur only after a strong level of electrostatic turbulence is achieved; this leads to the conclusion that the electrostatic turbulence is a major contributor to the shock dissipative process. This turbulence is best explained as the ion acoustic or Buneman mode due to two‐stream instability. One very thick shock structure is displayed which contains many very large amplitude and nearly reversible magnetic field pulsations.

The Pioneer 8 spacecraft was launched into an outbound heliocentric orbit on December 13, 1967. The payload includes a simple VLF electric field detector that uses the 423‐MHz antenna supplied for the Stanford radio propagation experiment. Broadband signals in the frequency range 0.1–100 kHz are examined by performing a pulse height analysis of the waveform, and wave amplitudes are also measured in bandpass channels centered at 0.4 and 22 kHz. It is found that low‐frequency electric field oscillations can always be detected in the solar wind, and that the amplitudes vary with changing interplanetary conditions. Large amplitude high‐frequency noise bursts are also detected sporadically, and we identify these as electron plasma oscillations in the solar wind.

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The TRW Systems electric field experiment on the USAF‐Aerospace Corporation spacecraft OV3‐3 (1966–70A) has one broadband channel and four bandpass channels covering the frequency range 20 Hz to 7.35 kHz, plus an onboard E, B correlator, which operates at a frequency of 400 Hz. The E‐field sensor is a short boom‐mounted asymmetric dipole that detects electric oscillations in the spacecraft equatorial plane. Examination of the angular distributions, and the loop and correlator response, allows electrostatic and electromagnetic waves to be distinguished. Details of the method of operation of the electric field sensor and related instrumentation are given, and preliminary results from the bandpass channels are displayed and discussed.