Temperature and Density Structures of Solar Corona, A Test of Iron Line Diagnostic Capability of EIS Instrument on Board Hinode
Increased diagnostic capability of the EUV Imaging Spectrometer (EIS) aboard Hinode (former Solar-B) has been demonstrated with a set of iron emission lines emerging in the two EIS observing wavelength bands (170-210Å and 250-290Å) and their line-intensity ratios. ``Abundance-uncertainty'' free relative emission measure distributions as a function of temperature were deduced using only iron emission lines of various ionization stages. First-light spectra of a small active region show iron lines ranging from FeVIII (185.2Å and 186.6Å) through FeXVII (204.7Å, 254.9Å, and 269.4Å). Spectra of a C-class flare confirms the presence of one of these higher temperature lines (FeXVII at 254.9Å) more clearly, as well showing FeXXIV (192.0Å and 255.1Å) and FeXXIII (263.8Å), which are normally only seen at flare temperatures.