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EISCAT Facility update 2013

EISCAT Facility update 2013. M. Kosch , Lancaster University , UK M . T. Rietveld EISCAT , Ramfjordbotn , Norway . 19th RF Ionospheric Interactions Workshop, 21 - 24 April 2013, Arecibo. Overview 1) EISCAT organisation and radar status 2) Heating status and recent results.

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EISCAT Facility update 2013

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  1. EISCAT Facility update 2013 M. Kosch, Lancaster University, UK M. T. Rietveld EISCAT, Ramfjordbotn, Norway. 19th RF Ionospheric Interactions Workshop, 21 - 24 April 2013, Arecibo.

  2. Overview 1) EISCAT organisation and radar status 2) Heating status and recent results

  3. EISCAT: Organisation EISCAT Scientific Association CAG Council Advisory Group

  4. EISCAT news • New director: Craig Heinselman (since January 2013) • UHF (933 MHz) radar now monostaticonly. GSM mobile phone network interference became too strong at Kiruna & Sodankyla. We are seeking licence extension beyond 2013. • VHF radar now tristatic: Kiruna & Sodankyla converted to 224 MHz. (But Tromsøremains non-field-aligned). Actually, it is tetrastatic, with the KAIRA receiver (LOFAR antenna at Kilpisjarvi, Finland) also receiving signals from the VHF radar. • EISCAT 3D: large funding proposals submitted by Norway and Sweden & hopefully Finland soon. Total cost estimate 132 M€. Core site selection still not decided, but near Ramfjordmoen, possibly further inland.

  5. transmitting antenna, 5.4 – 8 MHz receiving antenna, 5.4-8 MHz 4-5.4 MHz

  6. Heating Status, April 2013 Staffing: One scientist plus one engineer. Operations: 269 hrs in 2011, 263 hrs in 2012 Users from China, Finland, Japan, Norway, Russia, Sweden, UK, USA. Publications: 13in 2011, 6 in 2012, average about 10/yr which is about 20-25% of all EISCAT publications annually. Heating Technical status: Transmitters largely OK. One faulty transmitting tube is being rebuilt by Richardson Electronics (USA) to improve the spare part situation. Array 1 (30dBi gain): Serious rot was found in many of the small wooden poles supporting the feed lines. This array was rebuilt in 1990 and so is showing its age in some areas. Non-treated wood was used in some areas (not the main masts) since a 30+ year lifetime was never envisaged. Major upgrade work done in recent years on the RF generation, modulation and control hardware and software. Much greater flexibility, computer control of hardware and logging. For example instantaneous frequency/phase/amplitude stepping is possible.

  7. Transfer from Max-Planck to EISCAT

  8. Maintenance required on some ageing parts in antenna fields- rotting wood.

  9. Heater upgrade: developments and ongoing work • HF radar experiments with heating transmitters and Array-3 receiver in high demand: mostly low altitude (mesospheric) but also high-altitude (magnetospheric) experiments. • New hardware and software enables computer monitoring and control of certain transmitter hardware functions that were only available via lights and buttons on the console. • Fast frequency and/or phase and/or amplitude modulation is possible now. • Power calibrations and power stepping improved implementation. • Better logging of HF parameters. • Soon a modification to the coaxial switches will allow both reception and transmission on array-3 (5.4-8 MHz, 24 dBi gain).

  10. These buttons/lights are now under computer control.

  11. Using antenna array-3 as a receiver (presently with transmission line disconnected from transmitter) Power combiners Array-3 feed lines disconnected from transmitters

  12. New receiver connection to antenna (without opening the co-axial lines) summer 2013 to transmitter cable from tx/rx switch to power combiner or digital beam former to antenna (array-3)

  13. Recent scientific results X-mode excitation of irregularities and HFIL Backscatter enhancements on topside (very mysterious) Mesospheric HF echoes received in radar mode Mesospheric VHF echo modulation D-region heating model overestimates heating measured by riometerand cross-modulation experiments. Novel API (Artificial Periodic Irregularity) experiments Efficiency of resonant heating calculated. Ion upwelling studies

  14. Modelling the beam pattern with EZNEC suggests that the non-perfect ground may result in the antenna gain and ERP being only about 75% of that calculated assuming a perfect ground. This may help explain some of the discrepancy beyween calculated and measured heating effects in the D region. (e.g. Senior et al., JGR, 116, A04310, doi:10.1029/2010JA016189, 2011). Laying a ground plane of wires may be a relatively cheap way of increasing the effective radiated power. This is being investigated at present.

  15. 8 MHz echoes shown as contours on lower plot Mesospheric echoes 224 MHz echoes in colour with 8 MHz echoes shown as contours

  16. These apparent density increases are a mystery. But they are not real and are only seen very close to field-aligned See the recent paper by Senior et al., 2013 for details, GRL

  17. Examples of ion upwelling in the last few heater pulses(as well as the mysterious backscatter enhancements)

  18. Mesospheric velocities with API One advantage of the API method is that it allows high resolution vertical velocities to be measured between 50-120 km. Here is an example plot from our 9.12.2011 measurement. Around noon (7000 seconds in to the measurement) there are also some tropospheric echoes. -- from blog by JuhaVierinen: kaira.sgo.fi

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