Abstract—
The present work was to figure out whether intense current structures are formed in the quiet Plasma Sheet (PS) of the Earth’s magnetotail, or whether they are observed only in the presence of Bursty Bulk Flows (BBFs). We had statistically analyzed absolute value of electric current density \(\left| {\mathbf{j}} \right|\) , the magnitude of the nonideal electric field ( \({\mathbf{E}}{\kern 1pt} ' = {\mathbf{E}} + \left[ {{{{\mathbf{v}}}_{{\text{e}}}} \times {\mathbf{B}}} \right]\) , where \({{{\mathbf{v}}}_{{\text{e}}}}\) is electron bulk velocity, \({\mathbf{B}}\) and \({\mathbf{E}}\) are magnetic and observed electric fields, respectively) and the energy conversion rate \(\left( {{\mathbf{j}} \cdot {\mathbf{E}}{\kern 1pt} '} \right)\) observed by MMS spacecraft in 19 quite (the X-component of the ion bulk velocity \(\left| {{{{\mathbf{v}}}_{{{\text{i}}{\text{,}}x}}}} \right|\) < 200 km/s) and 23 active (peak value of \(\left| {{{{\mathbf{v}}}_{{{\text{i}},x}}}} \right|\) in each interval reaches at least 500 km/s) intervals. All observations were made in the midnight sector of the magnetotail ( \(\left| {{{Y}_{{{\text{GSE}}}}}} \right|~\,\, \leqslant ~\,\,13~{{R}_{{\text{E}}}}\) ) and within the Sun–Earth direction range \(X \approx ~\,\, - (15~-28)~{{R}_{{\text{E}}}}\) . It is shown that intense current structures with current density \(\left| {\mathbf{j}} \right|\) > 30 nA/m2 are observed only within the BBFs and are absent in the PS during quite intervals. The probability density distributions of \(\left| {{\mathbf{E}}{\kern 1pt} '} \right|\) , \(\left| {{\mathbf{E}}_{{||}}^{'}} \right|\) and \({\mathbf{j}} \cdot {\mathbf{E}}{\kern 1pt} '\) , \({{{\mathbf{j}}}_{{||}}} \cdot {\mathbf{E}}_{{||}}^{'}\) demonstrate similar behavior. Thus, during the quiet intervals, the typical values of \(\left| {{\mathbf{E'}}} \right|\) , \(\left| {{{{\mathbf{E}}}_{{||}}}'} \right|\) , and the parameters \({\mathbf{j}} \cdot {\mathbf{E}}{\kern 1pt} '\) and \({{{\mathbf{j}}}_{{||}}} \cdot {\mathbf{E}}_{{||}}^{'}\) do not exceed a few mV/m and tens of pW/m3, respectively. On the other hand, during the active intervals, \(\left| {{\mathbf{E}}{\kern 1pt} '} \right|\) and \(\left| {{\mathbf{E}}_{{||}}^{'}} \right|\) can exceed 10 mV/m, and the parameters \(\left| {{\mathbf{j}} \cdot {\mathbf{E}}{\kern 1pt} '} \right|\) and \(\left| {{{{\mathbf{j}}}_{{||}}} \cdot {\mathbf{E}}_{{||}}^{'}} \right|\) can exceed 100 pW/m3.
