Cluster observations of solitary structures in the vicinity of terrestrial bow shoock Conference Paper uri icon

abstract

  • Till now nonlinear short scale electric field structures are recognized as a ubiquitous phenomenon in the space plasma, as the means of transporting energy, momentum, and charge. In this paper we analyze a number of electrostatic solitary waves such as bipolar and unipolar/tripolar pulses in the weakly magnetized plasma observed in the foot region of a quasiperpendicular shock using Cluster to investigate the fundamental problems relating to the solitary waves such as their basic wave properties, generation mechanisms, significance in the plasma dynamics and the relevance of micro-structures (like solitary waves) to the macroscopic effect of shock structure. The properties of the solitary waves such as wave propagation direction, velocity, potential scale and amplitude are experimentally derived by means of the phase-differencing between two sets of parallel electric field vectors from Cluster electric field and wave measurements. The observed solitary waves are found to be an ion depletion structure such as BGK ion hole. Derived wave properties are compared with the predictions from analytical theory and numerical computations to study their excitation mechanisms in the foot region.

publication date

  • January 1, 2008