Abstract:
Observations from various interplanetary and other spacecraft missions evince that superthermal
distributions are omnipresent in the solar wind and near Earth’s plasma environment. These
observations confirm the presence of coherent bipolar electric field pulses. In phase space, these
electric field structures are observed as electron holes (EHs) or ion holes. Trapping of particles in a
potential well causes the formation of such structures and is generally studied using the BernsteinGreene-Kruskal approach. The literature on these structures encompasses the trapped electron
distribution function and physically plausible regions. In this paper, we focus on the effects of the
width and amplitude of wave potential on electron trapping in thermal and superthermal plasmas. It
can be observed that both an increase in the width and the amplitude of wave potential cause an
augmentation in the trapping of particles. The amplitude plays a dominant role in the trapping of
maximum energetic particles, whereas the width plays a role in deciding the density of particles at
the center of the EHs. We found that there exists an upper limit for the stability region of EHs
defined by the width-amplitude relation. Additionally, it is noticed that the superthermal plasma
does not impose restriction on the presence of electron holes with a width less than the electron
Debye length.
