1 - Nuclear Sciences and Applications - IAEA

IAEA-CN-50/E-I-4 557
This effect might explain the fact that C was less than 1. However, the energy
dependence of C suggested that the direct orbit loss was not negligible for higher
energetic protons.
It is concluded that this observation is the first experimental evidence showing
the possibility of confining high energy particles in a heliotron configuration. The
above-described results partially support our view that a reactor might be designed
on the basis of helical systems such as the heliotron/stellarator.
2. CHARACTERISTICS OF OVERDENSE PLASMAS DURING THE
SECOND AND THIRD HARMONIC ELECTRON CYCLOTRON
HEATING IN HELIOTRON DR
Experiments on the second and the third harmonic electron cyclotron heating
have been carried out in Heliotron DR (t = 2, m = 15, major radius R = 0.9 m,
mean minor radius a = 0.07 m, plasma volume Vp = 90 L) by using a 28 GHz,
200 kW gyrotron. The heating power'density attains ~2.4 W-cirT 3 , on the
average, which is fairly large compared with the values attained in Heliotron E
and Wendelstein VII-A (0.3 keV) signal, SX, is increased with n 100 keV) intensity, HX, is enhanced in the low density phase of
iie = (0.2-0.3) x 10 l3 cm" 3 and also during the rising phase of Wp. However, it is
strongly suppressed in the overdense regime. The time evolution of the soft X-ray
profile has been measured with a 12-chord silicon diode array. It shows that the