Origin and energy-exchange role of slow electron holes in the Earth's magnetosheath

Identify the source (generation mechanism) of slow electron holes observed in the Earth's magnetosheath and ascertain the role of these slow electron holes in electron–ion energy exchange within the magnetosheath plasma.

Background

The paper presents a statistical analysis of 645 solitary waves observed by MMS in the Earth's magnetosheath, showing that 630 are electron holes of positive polarity with parallel half-widths of 10–100 m and plasma-frame speeds around 100 km/s, well below the electron thermal speed and comparable to the ion thermal speed.

The authors argue these structures are slow electron holes and estimate an acceleration time scale of order one second due to interaction with ions. Despite this characterization, the generation mechanism of these slow electron holes and their quantitative contribution to electron–ion energy exchange remain unresolved within the presented observations and theory.