The Next Generation European Incoherent Scatter Radar System: EISCAT 3D and related facilities

The Next Generation European Incoherent Scatter Radar System: EISCAT 3D and related facilities Michael Rietveld EISCAT Scientific Association Tromsø Antenna 1 Control Norway Transmitter Antenna 2 Antenna 3 10th International Workshop on IPELS, Djurönäset, 8-12 June, 2009

Associate countries and institutes Contributing: European Incoherent Scatter Scientific Association Svalbard Sodankyla UHF Kiruna UHF Tromso VHF Tromso UHF 2 with thanks to the previous director, Tony van Eyken Tromso HF Heating

But EISCAT is not truly 3D (except for 1 point) We want to be able to look at a larger volume practically simultaneously. So as to resolve spatial-temporal ambiguities associated with the dynamic aurora To measure electric fields along a field-line (measure potential drops) We want essentially continuous operation and we want a near instantaneous response facility for unusual and unpredictable events We want a powerful, versatile facility to advance atmospheric, ionospheric, magnetospheric physics for the next generation of researchers

A design study was made between 2005 and 2009, at a cost of 4 M, largely funded by the EU. The final report was released last Friday, 05 June 2009. This 230-page document is available at www.eiscat3d.se

EISCAT_3D was added to the ESFRI (European Strategy Forum for Research Infrastructure) roadmap in Dec 2008

An operating frequency in the high VHF band (225-240 MHz) would ensure optimum performance in low electron density conditions (i.e. both in the middle atmosphere and in the topside ionosphere).

The core will comprise 1) a 120-m diameter filled circular aperture array with 16000 elements, laid out on an equilateral triangular grid, and 2) 2) a number (6 9) of smaller outlier receive-only arrays. It will provide: a half-power beamwidth of 0.75, i.e. comparable to that of the EISCAT UHF, a power-aperture product exceeding 100 GW m 2, i.e. an order of magnitude greater than that of the EISCAT VHF, grating-lobe free pattern out to 40 zenith angle, graceful degradation in case of single-point equipment failure. Each core array element will be made up from a radiator, a dual 300+300 watt linear RF power amplifier, a high performance direct-digitising receiver and support electronics. The recommended radiator is a crossed Yagi antenna with a minimum directivity of about 7 dbi.

Each of the 16000 antennas will have its own ~ 300+ W linear transmitter

EISCAT Scientific Association

To achieve the desired performance, the proposed system design incorporates a number of innovative, ground-breaking concepts, e.g. o Direct-sampling receivers o Digital time-delay beam-forming o Multiple simultaneous beams from each receiving array o Adaptive polarisation matching and Faraday rotation compensation o Digital arbitrary-waveform transmitter exciter system o Full interferometry and imaging capabilities o Amplitude-domain data recording at full sampling rate

Imaging simulations

Two filled 8000-element receive-only arrays will be installed on each baseline at distances of respectively 110 and 250 km from the core. Their radiating elements will be 3- or 4-element X Yagis, essentially identical to those used in the core. The Yagis will be directed towards the core field-of-view and elevated to 45. It will become possible, for the first time, to reconstruct the true vector E field through the whole ionosphere

Temporal and spatial resolutions will be increased by at least an order of magnitude compared to the existing systems. Science Drivers It has become increasingly clear that the processes which mediate even the largest scale effects are predominantly controlled by the physics of very small scale rapid interactions and this has led to a renewed interest in auroral electrodynamics and plasma physics. We need to study short time-scale, small spatial scale targets and processes typified by: Quasi-coherent echoes from small plasma targets in E and F regions, Controlled experiments on PMSE using the EISCAT Heater, Routine D-region /middle atmosphere incoherent scatter measurements, Statistics of E-region micrometeor head echoes for planetology, Instantaneous E fields at many altitudes along a whole magnetic field line, H/He/O ratios the in polar ionosphere Polar wind plasma outflow

Atmospheric Energy Budget Coupling processes Particle input Chemical coupling Dynamical coupling Ion-neutral neutral coupling Electrodynamics Flywheel effects Potential drops, acceleration Short-term term variability Long-term change Anthropogenic effects

Space Environment Space Weather Space debris Meteors Orbits Meteoric input Planetary Radars Near-Earth Objects Solar Wind measurements (and coronal radar)

Current best unfocussed images

Reach down to 600 m resolution

Dusty plasmas PMSE Aerosols Turbulence Neutral turbulence Plasma turbulence Space Plasmas Small-scale processes Auroral fine structure NEIALs (enhanced ion acoustic echoes) Thin layers Small-scale dynamics Large-scale processes Auroral forms Magnetospheric dynamics (Convection, storms, substorms) Reconnection Ion outflow

Auroral arc from ALLIS data, with viewpoint changing from Bjorn Gustavsson

EISCAT Scientific Association Example on volumetric data: PFISR Semeter et al., JASTP., 2008

These examples of enhanced ionacoustic spectra, associated with either filaments of large thermal or suprathermal (up to tens ev) electron flows were obtained with the Svalbard 500 MHz radar. They have small horizontal scales, and rapid (sub second) variations. At 230 MHz the threshold to observe them is lower.

Radio-induced optical emission over the heater in Ramfjord, near Tromsø, 16 Feb 1999. Viewer looking eastward. from Bjorn Gustavsson

Tromsø HEATING facility 12, 100-kW vacuum tube amplifiers, class AB temporary use as receive-only array

The facility started operation in 1980 It runs about 200 hours a year So it can probably run another 10 years or so without major repair costs. The low-power RF generation and control software has just been upgraded (DDS synthesizers- faster frequency changes) We are investigating operation at the 2nd gyroharmonic (2.71 MHz)

Characteristics of Heating phenomena Langmuir turbulence has time scales of milliseconds; thermal effects in the F region seconds. Horizontal Spatial scales of excited phenomena range from 10 s of m to ~100 km Many phenomena show a strong geometrical dependence on angle to the geomagnetic field. requiring volumetric imaging of the ionosphere within ± ca. 15 of HF beam direction.

Density depletion at the 10-m scale induced by the Arecibo heater M. C. Kelley, T. L. Arce, J. Salowey, M. Sulzer, W. T. Armstrong, M. Carter and L. Duncan (J. Geophys. Res. 100, 17367, 1995) Patches of filaments: 1.5-6 km Bunches of filaments: 60-600 m Diameter of filaments: 10 m Electron temperature structure? Radial and/or azimuthal motion? slide courtesy of T. Leyser, IRFU

Temporal evolution of pump beam self-focusing at the High- Frequency Active Auroral Research Program M. J. Kosch, T. Pedersen, E. Mishin, M. Starks, E. Gerken-Kendall, D. Sentman, S. Oyama and B. Watkins (J. Geophys. Res. 112, A08304, 2007) Pump frequency 2.85 MHz Oxygen 5577 Å emissions Self-focusing with collapse and intensification Fine scale structure: 2-6 km Electron temperature structure? 5577 Å First difference images Narrow field of view imager slide courtesy of T. Leyser, IRFU

Novel artificial optical annular structures in the high latitude ionosphere over EISCAT M. J. Kosch, M. T. Rietveld, A. Senior, I. W. McCrea, A. J. Kavanagh, B. Isham, and F. Honary (Geophys. Res. Lett. 31, L12805, 2004) -3 db locus of pump beam Heating beam scanning Annular structure for beam tilt 9 south EISCAT Heating Geomagnetic field Self-focusing with collapse and intensification Langmuir and/or UH waves? slide courtesy of T. Leyser, IRFU

Novel artificial optical annular structures in the high latitude ionosphere over EISCAT M. J. Kosch, M. T. Rietveld, A. Senior, I. W. McCrea, A. J. Kavanagh, B. Isham, and F. Honary (Geophys. Res. Lett. 31, L12805, 2004) Oxygen 5577 Å emissions Optical striations geomagnetic field-aligned Electron temperature structure? Langmuir or UH oscillations? The artificial auroral structure at 16:37:05 UT on12 November 2001, 5 s after HF pump turn on. Integration time =5 s. The image is taken in the zenith from Skibotn and has a 50º field of view (large circle). The -3 db locus of the pump beam assuming free space propagation is shown as a small circle (beamwidth = 7.4º), projected at 230 km altitude and tilted 9º south of the HF facility at Ramfjordmoen. The upper cross shows the location of the HF transmitter whilst the lower cross shows the magnetic field line direction (12.8º S), both projected at 230 km. The dotted line represents the magnetic field line connected to Ramfjordmoen and the labels give altitude.

Creation of visible artificial optical emissions in the aurora by high-power radio waves Todd. R. Pedersen and Elizabeth A. Gerken (Nature 433, 498, 2005) Pulsating aurora Pump on Speckles of pump-induced emissions at 5577 Å Unprecedented brightness Interaction with free energy sources What type of turbulence? Pump off slide courtesy of T. Leyser, IRFU

courtesy of Todd Pedersen

Topside Z-mode Z effect and the radio window 15:45:30 15:49:00 15:52:30 15:56:00 15:59:30 16:03:00 strong backscatter = coherent echoes Average of heater Cycles 3 4 320 320 320 320 320 320 3.5 2.5 300 280 300 280 300 280 300 280 Horizontally localised strong backscatter (antenna positions 1 apart, 30s in time) 300 Horizontally 300 localised 280 280 2 3 Altitude (km) 260 240 220 260 240 220 260 240 220 260 240 220 260 260 1.5 240 240 Vertically localised strong backscatter (range bins ca. 2 km apart) 220 220 ca. 2 km apart) 1 2.5 2 1.5 Raw backscattered power (db) 1 200 200 200 200 200 200 0.5 0.5 678 180 91011 12 678 180 91011 12 678 180 91011 12 678 180 91011 12 678 180 91011 12 678 180 9101 12 6 8 1012 20 40 60 Distance (km) 20 40 60 Distance (km) 20 40 60 Distance (km) 20 40 60 Distance (km) 20 40 60 Distance (km) 20 40 60 Distance (km) Ashrafi, Kosch et al., work in progress 0 20 40 60 Distance (km) 0

PMSE overshoot immediately after switching the 20s long heater pulse off. Smoothed data 20s 160s Total PMSE intensity (sum of highest intensities at each time sample) Raw data. (from Havnes et al., GRL, 30, 2229, 2003.)

Polar Mesospheric Winter Echoes (PMWE) Weaker than PMSE Lower altitude than PMSE Not associated with NLC Not during extreme cooling Want: Incoherent scatter spectra from 60-90 km with good (100 s s m) spatial resolution (to measue Te changes, and electron density bite-outs associated with PMSE)

Heating requirements of E3D Region Coherent Echo resolutions Height time horiz Incoherent Scatter resolutions Height time Horiz* 85 km < 100m 100ms 30m 1 km 1-10s10s 1 km 110 km 100m 10 ms 100m 1 km 1s 10m* 250 km 100m 10 ms 100m 1-22 km 1s 10m* Through Interferometry * = perpendicular to B, i.e. ca. 13 tilt to north

Funding and the future EISCAT-3D is on the ESFRI roadmap Norwegian government has promised to support the new radar Swedish national infrastructure application submitted for receiving sites in Sweden/Finland and a antenna- and test transmitter: decision in Sept 2009 (~10 M ) M Norwegian national infrastructure application submitted for the next stage of building the radar (~20 M ) M Preparation phase: Construction phase: Operation phase: 2009-2011 2011 2011-2015 2015 2015-2045 2045

http://uit.no/fysikk/eiscat2009ws