A SURVEY OF MAGNETIC WAVES EXCITED BY NEWBORN INTERSTELLAR He+ OBSERVED BY THE ACE SPACECRAFT AT 1 au

作者：Fisher Meghan K^*; Argall Matthew R; Joyce Colin J; Smith Charles W; Isenberg Philip A; Vasquez Bernard J; Schwadron Nathan A; Skoug Ruth M; Sokol Justyna M; Bzowski Maciej; Zurbuchen Thomas H; Gilbert Jason A

来源：Astrophysical Journal, 2016, 830(1): 47.

DOI：10.3847/0004-637X/830/1/47

• instabilities
• magnetic fields
• solar wind
• Sun: heliosphere
• turbulence
• waves

We report observations of low-frequency waves at 1 au by the magnetic field instrument on the Advanced Composition Explorer (ACE/MAG) and show evidence that they arise due to newborn interstellar pickup He+. Twenty-five events are studied. They possess the generally predicted attributes: spacecraft-frame frequencies slightly greater than the He+ cyclotron frequency, left-hand polarization in the spacecraft frame, and transverse fluctuations with minimum variance directions that are quasi-parallel to the mean magnetic field. Their occurrence spans the first 18 years of ACE operations, with no more than 3 such observations in any given year. Thus, the events are relatively rare. As with past observations by the Ulysses and Voyager spacecraft, we argue that the waves are seen only when the background turbulence is sufficiently weak as to allow for the slow accumulation of wave energy over many hours.

• 出版日期2016-10-10
• 单位Los Alamos