Observation of Bernstein Waves Excited by Newborn Interstellar Pickup Ions in the Solar Wind

• Published in: The Astrophysical journal Vol. 745; no. 2; pp. 112 - 8
• Main Authors: Joyce, Colin J, Smith, Charles W, Isenberg, Philip A, Peter Gary, S, Murphy, Neil, Gray, Perry C, Burlaga, Leonard F
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.02.2012; IOP
• Subjects: Astronomy; ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BERNSTEIN MODE; COSMIC RADIATION; Earth, ocean, space; Exact sciences and technology; Excitation spectra; Fluctuation; Interstellar; Jupiter; JUPITER PLANET; MAGNETIC FIELDS; PLASMA WAVES; POLARIZATION; SOLAR WIND; Spacecraft; Spectra; Voyager 2 spacecraft; VOYAGER SPACE PROBES; waves; Polarization; Fluctuations; Turbulence; cosmic rays; Voyager space probes; Bernstein mode; Magnetic fields; Jupiter planet; Cosmic radiation; Solar wind
• ISSN: 0004-637X; 1538-4357
• DOI: 10.1088/0004-637X/745/2/112

A recent examination of 1.9 s magnetic field data recorded by the Voyager 2 spacecraft in transit to Jupiter revealed several instances of strongly aliased spectra suggestive of unresolved high-frequency magnetic fluctuations at 4.4 AU. A closer examination of these intervals using the highest resolution data available revealed one clear instance of wave activity at spacecraft frame frequencies from 0.2 to 1 Hz. Using various analysis techniques, we have characterized these fluctuations as Bernstein mode waves excited by newborn interstellar pickup ions. We can find no other interpretation or source consistent with the observations, but this interpretation is not without questions. In this paper, we report a detailed analysis of the waves, including their frequency and polarization, that supports our interpretation.