Solitary structures associated with short large‐amplitude magnetic structures (SLAMS) upstream of the Earth's quasi‐parallel bow shock

Abstract

[1] For the first time, solitary waves (SWs) have been observed within short large-amplitude magnetic structures (SLAMS) upstream of the Earth's quasi-parallel bow shock. The SWs often occur as bipolar pulses in the electric field data and move parallel to the background magnetic field at velocities of v = 400-1200 km/s. They have peak-to-peak amplitudes in the parallel electric field of up to E 0 k = 65 mV/m and parallel scale sizes of L k $ 10 l D . The bipolar solitary waves exhibit negative potential structures of jF k j = 0.4-2.2 V, i.e., eF k /kT e $ 0.1. None of the theories commonly used to describe SWs adequately address these negative potential structures moving at velocities above the ion thermal speed in a weakly magnetized plasma.

Cluster and ACE observations of phase synchronization in intermittent magnetic field turbulence: a comparative study of shocked and unshocked solar wind

“…Stasiewicz et al (2003) reported the measurement, on 3 February 2002, of the density profiles and wave spectra inside fast magnetosonic shocklets, 1000 km in size and amplitude of 10 times the ambient magnetic field, upstream of a quasi-parallel bow shock. Behlke et al (2004) observed on 3 February 2002 solitary waves, as bipolar pulses in the spiky electric field moving at velocities of 400-1200 km/s along the ambient magnetic field with peak-to-peak amplitudes of E =65 mV/m and parallel scale sizes of L ∼300−600 m∼10λ D (Debye length), within short large-amplitude magnetic structures (SLAMS) upstream of a quasi-parallel bow shock. In addition, Parks et al (2006) detected ion density holes accompanied by magnetic holes (∼3700 km) upstream of a quasi-parallel bow shock, which are seen only with upstream particles, suggesting a link with backstreaming particles interacting with the solar wind.…”

“…2. This quasiparallel shock event has been analyzed by a number of papers (Eastwood et al, 2003;Stasiewicz et al, 2003;Behlke et al, 2004;Lucek et al, 2004). As mentioned in the Introduction, when the Cluster spacecraft navigate in the upstream solar wind they stay always very close to the bow shock, as a result magnetic connections to the bow shock occur frequently (Kellogg and Horbury, 2005 .…”

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

“…Since then, they are commonly observed in auroral regions (Ergun et al, 1998; 2001; Pickett et al, 2004) but also in several Earth magnetic environments (Matsumoto et al, 1994;Franz et al, 1998;Cattell et al, 2003;Pickett et al, 2003) and in the Earth bow shock (Bale et al, 1998;Behlke et al, 2004). Evidence for the presence of isolated bipolar electrostatic structures in the solar wind is more recent: Mangeney et al (1999) first reported the observation of such structures in the free solar wind and Williams et al (2006) showed some examples associated to an interplanetary shock.…”

Shocks in collisionless plasmas

“…The bursty broadband emissions observed up to the electron plasma frequency are probably associated with electrostatic solitary structures traveling along B (Behlke et al 2004). Electric field associated with nonlinear interactions can heat electrons inside DHs beyond the adiabatic effects (Lembège et al 2003) and heating of particles can also occur by ion-streaming instability across the bow shock (Yang et al 2014).…”