"Probe No. 2" Satellite Launched
At 18" 5' 15 o'clock of July 25, Beijing time,
the " Probe No. 2" satellite was sent into the space successfully
by the modified rocket "Long March II C" at the Taiyuan Satellite
Launching Centre in China. It is an indication that the "Geospace
Double Star Probe Program" being carried out by our country has been
achieved successfully. Combined with the "magnetic layer Probe program"
of the European Space Bureau, the six points and three-dimensional detection
to the geospace were realized for the first time in the human history.
Big breakthrough was made in the high temperature
plasma physics experiments held between Apr. 11 and Jun. 14, 2004. Plasma
discharges were maintained for about 240 seconds, breaking the 100 seconds
threshold. Abundant and fruitful researches have been conducted.
The physicists worked in five topic groups, including
Long Pulse and Steady State Plasma Technology, Core Plasma Confinement
and Transport, MHD Analysis and Control, Boundary Plasma and Plasma Surface
Interaction. Productive experiments were carried out on sixteen topics,
such as Synergy of Low Hybrid Wave and Ion Bernstein Wave, Feedback Control
of MHD Activities Under High Power Heating, Turbulence and Boundary Transport,
Density Limit and Multifaceted Asymmetric Radiation From the Edge (MARFE),
Omegatron Probe, etc. Among all the progress, the greatest breakthrough
was made on long pulse operation with low hybrid wave current driving.
The maximum pulse duration reached about 240 seconds.
In addition, during this experiment, scientists from National Institute for Fusion Science (Japan), Kyushu University (Japan), Massachusetts Institute of Technology (America) and the University of Texas (America) joined the experiments with their own proposals, data analysis codes or diagnostic systems. The cooperation turns out to be satisfactory.
Research on High Power VCSELs
Achieves World-level Results
980nm high power VCSEL, a major research project,
undertaken by a cooperative research group with Changchun Institute of
Optics, Fine Mechanics and Physics (CIOMP), and Institute of Physics,
CAS has passed the technical appraisement on May 30, 2004. Committee of
experts concluded that the large diameter vertical cavity surface emitting
lasers (VCSELs) developed by the group achieved many world-level results.
As explained by Prof. Lijun Wang, VCSELs has
many advantages, such as excellent light beam quality and large-scale
integration compared with conventional edge-emitting lasers. It was the
first time that high thermal conducting Al2O3 film was used as the passivation
layer to decrease non-radiation combination and threshold current density.
It was also the first time that HfO2-based multi-layer was used as the
light emission window. These approaches bring about a breakthrough progress
in the research of high power VCSELs. High output power of 1.95W in continuous
wave operation was realized for large-diameter VCSELs with diameters of
500mm, 600mm and 700mm. A VCSEL with a diameter of 200mm exhibited an
output power as high as 10.5W and a power density of 33.4KW/cm2. A 300mm-diameter
VCSEL demonstrated a CW output power of 1.11W with a power density of
1.57KW/cm2. All the results above were higher than other similar devices
reported abroad. The lifetime of the devices was beyond 4500 hours.
copyright © 1998-2005