The EUVE and the Ionization in the Local Interstellar Cloud

EUVE white swarfs spectra analyses have provided HI, HeI and HeII column-densities in the ISM between the Sun and the target stars, and as a result the mean ionization in the local gas in different directions. It is found that, while hydrogen seems to be increasingly ionized in the direction of the so-called Canis Major tunnel, helium does not follow any trend, and seems to be uniformly ionized at 40 ionization gradient is consistent with other determinations of the electron density in the Local Interstellar Cloud, including the circumsolar ISM electron density from both EUVE and SOHO observations. We discuss this gradient and the local ISM ionization state.