First observations of SPEAR-induced artificial backscatter from CUTLASS and the EISCAT Svalbard radars

• Main Authors: Robinson, T. R., Yeoman, T. K., Dhillon, R. S., Lester, M., Thomas, E. C., Thornhill, J. D., Wright, D. M., van Eyken, A. P., Mccrea, I. W.
• Other Authors: Department of Physics and Astronomy Leicester, University of Leicester, EISCAT Scientific Association, Space Science and Technology Department Didcot (RAL Space), STFC Rutherford Appleton Laboratory (RAL), Science and Technology Facilities Council (STFC)-Science and Technology Facilities Council (STFC)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2006
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Svalbard; Svalbard Archipelago; Tromsø; EISCAT; Spitzbergen
• Online Access: https://hal.science/hal-00317935; https://hal.science/hal-00317935/document; https://hal.science/hal-00317935/file/angeo-24-291-2006.pdf

International audience Results are presented from the first two active experimental campaigns undertaken by the new SPEAR (Space Plasma Exploration by Active Radar) high-power system that has recently become operational on Spitzbergen, in the Svalbard archipelago. SPEAR's high-power beam was used to excite artificial enhancements in the backscatter detected by the ESR (EISCAT Svalbard Radar) parallel to the geomagnetic field, as well as coherent backscatter detected by both of the CUTLASS (Co-operative UK Twin Located Auroral Sounding System) coherent radars, in directions orthogonal to the geomagnetic field. The ESR detected both enhanced ion-lines as well as enhanced plasma-lines, that were sustained for the whole period when SPEAR was transmitting ordinary mode radio waves, at frequencies below the maximum F-region plasma frequency. On a number of occasions, coherent backscatter was also observed in one or in both of the CUTLASS radars, in beams that intersected the heated volume. Although the levels of enhanced backscatter varied considerably in time, it appeared that ion-line, plasma-line and coherent backscatter were all excited simultaneously, in contrast to what has typically been reported at Tromsø, during EISCAT heater operations. A description of the technical and operational aspects of the new SPEAR system is also included.