Abstract: A plasma generating apparatus and a method for controlling plasma-generating high frequency power capable of appropriately and easily controlling plasma density over the long term are disclosed. Measuring high frequency power is supplied to plasma through a dielectric tube. Apart from a supply system of plasma-generating high frequency power, there is provided a plasma density information obtaining section having long lifetime no hot filament. The plasma density information obtaining section obtains the plasma density information by measuring a physical amount related to reflection or absorption of the high frequency power. An actually measured plasma density monitored by the plasma density information obtaining section from moment to moment and a target plasma density held in a plasma density setting section are compared.

Abstract: The present invention relates to a method of and an apparatus for emitting light in ice, to be applied to an ice skating rink and the like. With the apparatus for emitting light in ice according to the present invention, when light emission sources are light emitting diodes (LED), LED mounting blocks are used and laid on a concrete floor, so that mounting works can be facilitated. Additionally, LED are used as the light emission sources, so that a possibility of ice melting can be eliminated. Furthermore, with the apparatus for emitting light in ice according to the present invention, when miniature incandescent bulbs are used as the light emission sources, the miniature incandescent bulbs disposed in transparent vinyl chloride tubes are laid on the concrete floor, so that a special water-proof measure can be dispensed with. Furthermore, air is delivered into the tube, whereby heat in the tube is prevented from being stagnant in the tube, so that the ice melting is avoided.