In order to better understand the nature of active region outflows , the electron density was measured by using a density-sensitive line pair Fe xiv 264.78 Å/ 274.20 Å .
Since coronal line profiles of the outflow region are composed of a major component with a Doppler shift of \leq 10 \mathrm { km } \mathrm { s } ^ { -1 } and a minor component ( enhanced blue wing : EBW ) blueshifted by up to 100 \mathrm { km } \mathrm { s } ^ { -1 } , we extracted EBW from the line profiles through double-Gaussian fitting .
We tried applying the simultaneous fitting to those two Fe xiv lines with several physical restrictions .
Electron density for both components ( n _ { \mathrm { Major } } and n _ { \mathrm { EBW } } , respectively ) was calculated by referring to the theoretical intensity ratio as a function of electron density as per the CHIANTI database .
We studied six locations in the outflow regions around NOAA AR10978 .
The average electron density was n _ { \mathrm { Major } } = 10 ^ { 9.16 \pm 0.16 } \mathrm { cm } ^ { -3 } and n _ { \mathrm { EBW } } = 10 ^ { 8.74 \pm 0.29 } \mathrm { cm } ^ { -3 } .
The magnitude relationship between n _ { \mathrm { Major } } and n _ { \mathrm { EBW } } was opposite in the eastern and western outflow regions .
The column depth was also calculated for each component , which leads to the result that the outflows possess only a small fraction ( \sim 0.1 ) in the eastern region , while they dominate over the major component in the line profiles by a factor of five in the western region .
When taking into account the extending coronal structures , the western region can be thought to represent the mass leakage .
In contrast , we suggest a possibility that the eastern region actually contributes to the mass supply to coronal loops .