In this paper , we study the temperature and density properties of multiple structural components of coronal mass ejections ( CMEs ) using differential emission measure ( DEM ) analysis .
The DEM analysis is based on the six-passband EUV observations of solar corona from the Atmospheric Imaging Assembly onboard the Solar Dynamic Observatory .
The structural components studied include the hot channel in the core region ( presumably the magnetic flux rope of the CME ) , the bright loop-like leading front ( LF ) , and coronal dimming in the wake of the CME .
We find that the presumed flux rope has the highest average temperature ( > 8 MK ) and density ( \sim 1.0 \times 10 ^ { 9 } cm ^ { -3 } ) , resulting in an enhanced emission measure ( EM ) over a broad temperature range ( 3 \leq T ( MK ) \leq 20 ) .
On the other hand , the CME LF has a relatively cool temperature ( \sim 2 MK ) and a narrow temperature distribution similar to the pre-eruption coronal temperature ( 1 \leq T ( MK ) \leq 3 ) .
The density in the LF , however , is increased by 2 % to 32 % compared with that of the pre-eruption corona , depending on the event and location .
In coronal dimmings , the temperature is more broadly distributed ( 1 \leq T ( MK ) \leq 4 ) , but the density decreases by \sim 35 % to \sim 40 % .
These observational results show that : ( 1 ) CME core regions are significantly heated , presumably through magnetic reconnection , ( 2 ) CME LFs are a consequence of compression of ambient plasma caused by the expansion of the CME core region , and ( 3 ) the dimmings are largely caused by the plasma rarefaction associated with the eruption .