Kinetic-scale Current Sheets in the Solar Wind at 1 au: Scale-dependent Properties and Critical Current Density

We present analysis of 17,043 proton kinetic-scale current sheets (CSs) collected over 124 days of Wind spacecraft measurements in the solar wind at 11 samples s(-1) magnetic field resolution. The CSs have thickness, lambda, from a few tens to one thousand kilometers with typical values around 100 km, or within about 0.1-10 lambda(p) in terms of local proton inertial length, lambda(p) . We found that the current density is larger for smaller-scale CSs, J (0) approximate to 6 nAm(-2) center dot (lambda/100 km)(-0.56), but does not statistically exceed a critical value, J(A) , corresponding to the drift between ions and electrons of local Alven speed. The observed trend holds in normalized units: J(0)/J(A) approximate to 0.17 center dot(lambda/lambda(p))(-0.51) Delta theta approximate to 19 degrees center dot(lambda/lambda(p))(0.5)

Automated summary

In this study, we analyzed proton kinetic-scale current sheets in the solar wind and found that smaller-scale current sheets have higher current density, but do not exceed the drift between ions and electrons of local Alven speed. This observation holds in normalized units.