Paper presented at the EGS General Assembly, 21-25, April, 1997, Vienna, Austria
The time-of-flight mass spectrometer HSTOF of the CELIAS experiment on SOHO has the capability of detecting energetic neutral hydrogen atoms (ENHAs) between 50 and 80keV. We shall report on the ENHA flux limits derived from the data collected since launch and discuss the implications of this observation on the existing models of energetic neutral atom (ENA) production in the heliosphere, i.e. outer heliosphere, co-rotating interaction regions and/or coronal or solar mass ejections.