Thermal Continuum Radiation from Coronal Plasmas at Soft X-ray Wavelengths

The continuous spectra, arising from the free-free and free-bound transitions of electrons in coronal plasmas, are calculated for wavelengths in the range 1 Å to 30 Å and at temperatures in the range $$0.8 10^{6} \,^{\circ}K \,\text{to} \,100.0 \,10^{6} \,^{\circ}K.$$ The effect of variations in the element abundances is investigated. Estimates of the continuum flux from the solar corona are presented and the observed line to continuum ratios discussed.