Whistler waves, Langmuir waves and single loss cone electron distributions inside a magnetic cloud: Observations

Abstract

Abstract. Whistler waves propagating along the ambient magnetic field are observed within a coronal mass ejection (on January 10, 1997) associated in time with Langmuir waves and electron distributions of a single loss cone type. In addition, background observations are made on the plasma wave activity in the sheath and foreshock regions that precede the magnetic cloud, on the observed radio emissions (including a type II radio burst) and on the geometry of the cloud. All the data comes from the WIND spacecraft. The whistler waves are identified using full magnetic waveforms while possible evidence of coexisting parallel, and antiparallel propagating Langmuir modes are found in the waveform and spectral wave data from the WAVES experiment. A few hundred low energy electron distributions from the Three-Dimensional Plasma (3DP) experiment are investigated. Finally, we tentatively suggest that this type of plasma wave particle activity is linked to the type II emission observed, i.e., that the emission mechanisms are proceeding and taking place within the magnetic cloud instead of at the shock region as usually thought. The extra suprathermal electrons could source from electrons accelerated at reconnection sites between the magnetic cloud and the ambient interplanetary magnetic field. A linear instability study using observed properties of the electron distributions is to be presented in a following paper.

Plasma waves above the ion cyclotron frequency in the solar wind: a review on observations

“…9) reveals that the waves are planar, (right-handed) circularly polarized. Contrary to the results of Coroniti et al (1982) who found waves propagating at large angle to the magnetic field background, the observations of Moullard et al (2001) seem to show a propagation aligned with the interplanetary magnetic field. This discrepancy can be explained by an incorrect identification of the waves in the former case.…”

“…Lin et al (1997Lin et al ( , 1998) also showed that the occurrence of these waves was associated with enhanced heat flux conditions. Moullard et al (2001) observed whistlermode waves in magnetic clouds. The electric and magnetic waveforms measurements analysis (Fig.…”

“…This magnetic activity is enhanced in case of disturbances of the solar wind like near interplanetary shocks , high-speed streams (Coroniti et al, 1982;Lin et al, 1997;Lengyel-Frey et al, 1996) or magnetic clouds (Moullard et al, 2001). It does not exhibit any specific dependence with latitude (Lengyel-Frey et al, 1996).…”

“…The analysis of the electron distribution function at the time of increased activity of whistler-modes show the presence of loss cone oriented either sunward or anti-sunward (Fig. 7 of Moullard et al, 2001). These observations favor the idea of a local generation of the waves; still a lot of observations and theoretical developments are required to explain the mechanisms leading to the formation of these very low frequency waves.…”

Electromagnetic waves and electron anisotropies downstream of supercritical interplanetary shocks

“…WWs have been observed in nearly every space plasma environment including, but not limited to, the terrestrial magnetosphere [e.g., Russell et al, 1969], in the solar wind [e.g., Coroniti et al, 1982], upstream of IP shocks [e.g., Russell et al, 1983;Wilson III et al, 2009], downstream of IP shocks [Moullard et al, 1998[Moullard et al, , 2001], upstream of planetary bow shocks [e.g., Hoppe et al, 1981], and in the ramp of supercritical IP shocks [Wilson III et al, 2012].…”