CRYOGEN FREE HIGH-TEMPERATURE SUPERCONDUCTING MAGNETS FOR 94 GHZ GYROKLYSTRON-POWERED RADAR APPLICATIONS

There is current interest within the Navy to develop high average powe r gyroklystron amplifiers to generate millimeter wave electromagnetic radiation for enhanced performance W-band (94 GHz) radar applications. These applications include high resolution imaging, precision trackin g, and cloud physics studies. Notwithstanding the relatively high atmo spheric absorption in the high frequency millimeter wave bands, the de velopment of radars in these frequency bands can solve many pressing p roblems, provided sufficient power levels can be obtained. Gyroklystro n amplifiers are vacuum electronic amplifiers which are capable of pro viding more than an order of magnitude increase in power over conventi onal coupled-cavity TWTs in these bands. One current frequency of inte rest is in the 94 GHz range which requires an external magnetic field of similar to 3.4 Tesla in order for the gyroklystron to operate. The most efficient means for generating this magnetic field level is throu gh the use of superconducting magnets. With the continued development of high temperature superconductors (HTS) and a corresponding progress in cryo-cooler technology, it is now possible to consider utilizing c ryo-cooled HTS in this application. Operating in the 10 K to 25 K rang e with a cryo-cooler, we are currently developing a prototype cryogen free HTS magnet system for this radar application.