EXCITATION OF LOW-FREQUENCY WAVES IN THE SOLAR WIND BY NEWBORN INTERSTELLAR PICKUP IONS H{sup +} AND He{sup +} AS SEEN BY VOYAGER AT 4.5 AU

Journal Article · Wed Dec 01 00:00:00 EST 2010 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/724/2/1256· OSTI ID:21474493

Joyce, Colin J; Smith, Charles W; Isenberg, Philip A ^[1]; Murphy, Neil ^[2]

---

1. Physics Department, Space Science Center, University of New Hampshire, Durham, NH (United States)
2. Space and Astrophysical Plasmas Group, Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA (United States)

We report the observation of a spectral enhancement in the magnetic field fluctuations measured by the MAG instrument on the Voyager 2 spacecraft during 4.5 hr on DOY 7, 1979 at a heliocentric radial position of 4.5 AU. This time period is contained within a solar wind rarefaction when the large-scale interplanetary magnetic field was nearly radial. The frequency range and polarization of the enhanced fluctuations are consistent with waves generated by newly ionized interstellar H{sup +} and He{sup +}. We show sunward propagation of the waves via a cross-helicity analysis. We compare the observation with a theoretical model and find reasonable agreement given the model assumptions. This event is the first indication of pickup ion-generated waves seen at Voyager. It is also the first identification of pickup He{sup +} waves by any spacecraft.

• OSTI ID: 21474493
• Journal Information: Astrophysical Journal, Vol. 724, Issue 2; Other Information: DOI: 10.1088/0004-637X/724/2/1256; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ABUNDANCE
HELIUM IONS
HYDROGEN IONS 1 PLUS
INSTABILITY
INTERPLANETARY MAGNETIC FIELDS
POLARIZATION
SOLAR WIND
VOYAGER SPACE PROBES
CATIONS
CHARGED PARTICLES
HYDROGEN IONS
IONS
MAGNETIC FIELDS
SOLAR ACTIVITY
SPACE VEHICLES
STELLAR ACTIVITY
STELLAR WINDS
VEHICLES