BEIJING, Jan. 22 (Xinhua) -- Chinese scientists announced they have more than doubled the temperature in the Chengdu-based experimental thermonuclear fusion reactor to 55 million degrees Celcius -- still barely half the temperature needed to provide energy.

    The test was conducted in Southwestern Research Institute of Physics under the Chinese Academy of Sciences in Chengdu, capital of Sichuan Province, last December.

    Thermonuclear fusion requires a temperature of over 100 million degrees Celsius to produce energy, said scientists. After that temperature, deuterium and tritium atoms are forced together to form a super heated plasma which should begin to give off its own energy, scientists explain.

    "At present, Europe and the United States have been able to acquire plasma at that temperature," said Liu Yong, director of the Center for Fusion Science with the institute.

    Fusion reaction is an attempt to replicate the energy generating process of the sun.

    China has two major experimental fusion devices. EAST (experimental advanced super conducting Tokamak) is located in Hefei, capital of east China's Anhui Province, while the other is the HL-2A experimental thermonuclear fusion reactor in Chengdu.

    EAST is China's upgrade of the first-generation Tokamak reactor, said Chinese scientists.

    In 2003, China joined the 4.6-billion-euro ITER (International Thermonuclear Experimental Reactor), the largest international program dedicated to experiments in thermonuclear fusion.

    China is one of the seven participants in the international cooperation program, which also includes the United States, the European Union, the Republic of Korea, Russia, Japan and India.

    About 2,000 Chinese researchers are engaged in the study of thermonuclear fusion.