SSX Photos/title> <link rel="shortcut icon" href="../favicon.ico" /> </head> <body alink="blue" link="#0033CC" vlink="#993333" text="black"> <font color="#FFFFFF"></font> <p><font color="#000000"></font> </p> <table width="800" border="1" bgcolor="#CCFFCC" align="center" cellpadding="10"> <tr> <td align="center" valign="top"><p><font color="#000000" style="font-size:14pt">Photos from the SSX lab<br /> </font><a href="index.html">Home<font color="#FFFFFF"></font></a></p> </td> </tr> <tr> <td><div align="center"> <p><img src="SSXpic8_15.JPG" width="512" height="384" /></p> <p align="left">A side view of the SSX vacuum chamber. Hydrogen gas is injected into the plasma guns on either side of the machine (one gun can be clearly seen on the left side of the photo) and then ionized by a 5000 V potential difference across the inner and outer gun electrodes. The wire coil surrounding the gun supplies the magnetic "stuffing field" that becomes the poloidal field of the spheromak after it is ejected from the gun. The toroidal magnetic field is created by the current that flows along the inner gun electrode when the main capacitor banks discharge. Several experimental diagnostics are visible on the side of the machine--the wires entering the vacuum chamber on the upper left and right are connected to magnetic probe arrays, and the upper port on the center flange contains the four soft x-ray detector (SXR) filters.</p> <p align="center"><img src="Heglowpic8_15.JPG" width="512" height="384" /></p> <p align="left">Looking through a window during helium glow discharge cleaning. Glow discharge cleaning uses helium plasma to remove impurities from the walls of the flux conserver, thereby allowing us to create hotter, less dense hydrogen plasma. The blue glow seen through the gap in the flux conserver walls is emission from the helium plasma. The mach probe, used to measure bulk flow velocities in the plasma, can also be seen.</p> <p align="center"><a name="Lollipop" id="Lollipop"></a><img src="Lollipoppic8_15.JPG" width="512" height="384" /> </p> <p align="left">The device (affectionately renamed the "lollipop" by Doc) that Chris and I built to test visible and UV transmission through the SXR filters. The larger piece of glass is UV fused silica, with transmission above approximately 170 nm, and the smaller piece of glass is sapphire, with transmission above approximately 150 nm. Once the device was inserted into the machine through the port directly below SXR, we loosened one of the screws and rotated the sapphire window 90 degrees. Once the machine was sealed back up, we could then rotate the shaft to have either of the windows blocking the SXR line of sight.</p> <p align="center"><img src="Lollipopinsidepic8_15.JPG" width="512" height="384" /> </p> <p align="left">After the lollipop device was installed, the sapphire window is visible inside the machine. The soft x-ray detector is connected to the flange just out of the top of the image--in order to block it with the sapphire lens, all we had to do was rotate the shaft counterclockwise.</p> <p align="center"><img src="Plasmapic8_15.JPG" width="512" height="384" /></p> <p align="left">A view of the plasma during a standard SSX shot. The light appears purple because of emission from Balmer series hydrogen lines that appear during recombination of protons and electrons. The SSX plasma only lives for about 100 μs, so Doc had to use some amazing timing and a long exposure to capture this one. </p> </div></td> </tr> <tr> <td><div align="center">This page was last updated on 8/15/06</div></td> </tr> </table> </body> </html>