  We present observations of the North Polar Spur (NPS) using the X-ray Imaging
Spectrometer (XIS) aboard the Suzaku X-ray satellite. The NPS is a large region
of enhanced soft X-ray and radio emission projected above the plane of the
Galaxy, likely produced by a series of supernovae and stellar winds from the
nearby Sco-Cen OB association. The exceptional sensitivity and spectral
resolution of the XIS below 1 keV allow unprecedented probing of low-energy
spectral lines, including CVI (0.37 keV) and NVII (0.50 keV), and we have
detected highly-ionized nitrogen toward the NPS for the first time. For this
single pointing toward the brightest 3/4 keV emission (l = 26.8 deg, b = +22.0
deg), the best-fit NPS emission model implies a hot (kT ~ 0.3 keV), collisional
ionization equilibrium (CIE) plasma with depleted C, O, Ne, Mg, and Fe
abundances of less than 0.5 solar, but an enhanced N abundance, with N/O = 4.0
+0.4,-0.5 times solar. The temperature and total thermal energy of the gas
suggest heating by one or more supernovae, while the enhanced nitrogen
abundance is best explained by enrichment from stellar material that has been
processed by the CNO cycle. Due to the time required to develop AGB stars, we
conclude that this N/O enhancement cannot be caused by the Sco-Cen OB
association, but may result from a previous enrichment episode in the solar
neighborhood.
