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1 HEATING expands the mind EISCAT training course.

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Presentation on theme: "1 HEATING expands the mind EISCAT training course."— Presentation transcript:

1 1 HEATING expands the mind EISCAT training course

2 2 The past G. Marconi ( ) Nobel Prize 1909 Earth There had to be a reflecting layer in order to explain his trans-Atlantic radio wave connection. Reflecting layer at km altitude (the ionosphere) Radio Sender Receiver

3 3 Tesla developed high-frequency high-power generators The past The past N. Tesla ( )

4 4 The past At the same time as Marconi, Tesla wanted to transmit energy as well as information using wireless radio waves. He built a transmission tower for this pupose. However, his work had little to do with modern ionospheric research.

5 5 The past Geometry of the Luxembourg effect (Tellegen, 1933)

6 6 EISCAT consists of much more than just radars. It possesses the world‘s largest high-frequency (HF) ionospheric modifi- cation facility, called HEATING or simply the HEATER. Built by the Max- Planck-Society in the late 1970s, it passed to EISCAT in EISCAT mainland

7 7 A geographic overview of the EISCAT radar, HEATING & SPEAR HF facilities and CUTLASS coherent scatter radars

8 8 Antenna 1 Antenna 2 Antenna 3 Transmitter The Heating facility at Tromsø Control

9 9 Tromsø HEATING facility layout

10 10 HEATER control house with EISCAT radars in the background

11 11 A single HEATING antenna

12 12 An antenna array

13 13 Transmitters Transmitters during construction: 6 of 12

14 14 Only 50 km of home-made aluminium RF coaxial transmission lines with mechanical switches Coax

15 15 Thermal expansion: Thermal expansion: One of many detours

16 16 2 Antennas give a broad beam 4 Antennas give a narrower beam with more power in the forward direction and less power in all other directions. Effective Radiated Power Effective Radiated Power = Radiated power  Antenna gain At Heating At Heating: 300 MW = 1.1 MW  270 for low gain antennas 1.2 GW = 1200 MW = 1.1 MW  1100 for high gain antenna Beam forming

17 : Platteville, Colorado 1975: SURA (Nizhni Novgorod), Russia ~1980: Arecibo (Puerto Rico), Tromsø (Norway), HIPAS (Alaska) 1995: HAARP (Alaska) 2003: SPEAR (Svalbard) World overview

18 18 A comparison HEATINGSPEARHAARP HEATINGSPEARHAARP (final) Power (MW): Antenna24 and 3016 & 2230 Gain (dB): ERP (MW):300 & & Freq. (MHZ): & & Polarisation:O & XO & XO & X Beamonly north-southanyany Steering:relatively slow fastfast Diagnostics:KSTESR? CUTLASSCUTLASSKODIAK Dynasonde?Digisonde

19 19 The ionosphere F c = 8.98*sqrt(N e ) for O-mode F c = 8.98*sqrt(N e ) + 0.5*Be/m for X-mode

20 20 A comparison of frequency range and effective radiated power of different facilities 1GW 100 MW 10 MW SPEAR

21 21 Why do we need the HEATING facility? true Why?: HF facilities are the only true active experiments in the ionosphere because the plasma may be temporarily modified under user control. Operations: ~200 hours per year (1 year=8760 hours), mostly in user-defined campaign mode. Experiments can be divided into 2 groups: Plasma physics investigations: the ionosphere is used as a laboratory to study wave-plasma turbulence and instabilities. Geophysical investigations: ionospheric, atmospheric or magnetospheric research is undertaken.

22 22 The Incoherent Scatter RadarSpectra with Ion and Plasma lines corresponding to ion-acoustic waves and Langmuir waves The Incoherent Scatter Radar Spectra with Ion and Plasma lines corresponding to ion-acoustic waves and Langmuir waves Langmuir turbulence, the parametric decay instability: e/m pump(  0,0)  Langmuir(  0 -  ia,-k) + IonAcoustic(  ia,k) Langmuir(  0 -  ia,-k)  Langmuir(   ia,k) + IonAcoustic (  ia,-2k) The component of the pump electric field parallel to the Earth's magnetic field is what matters. Thermal resonance instability: e/m pump + field-aligned electron density striation  electrostatic wave (UH) Upper hybrid (UH) resonance condition:  0 2 =  p 2 +  e 2 The component of the pump electric field perpendicular to the Earth's magnetic field is what matters.

23 23 PLASMA TURBULENCE HF on HF off UHF ion line spectra 12 Nov MHz ERP = 830 MW O-mode

24 24 The UHF radar observes HF pump- induced plasma turbulence MHz ERP = 1.1 GW O-mode PLASMA TURBULENCE

25 25 PLASMA TURBULENCE Z-mode penetration of the ionosphere

26 26 HF pump-induced magnetic field-aligned electron density irregularities (up to ~5%) causes coherent radar reflections and anomalous absorption (by scattering) of probing signals.Striations

27 27 HF induced F-region CUTLASS radar backscatter

28 28 Amplitude of radio waves received from the satellite Striations

29 29 After HF pump off, the irregularities decay with time Striations

30 30 Tromsø HF induced E-region STARE backscatter (144 MHz)

31 31  Heater on Artificially raised electron temperatures 16 Feb MHz ERP = 75 MW O-mode

32 32 HF pump-induced artificial optical emissions 16 Feb MHz ERP = 75 MW O-mode 17:40 HF on 17:44 HF off

33 33 HEATER and UHF beam swinging UHF zenith angle 7 Oct MHz ERP = 100 MW O-mode

34 34 ARTIFICIAL AURORA shifted onto magnetic field line 21 Feb nm Start time: UT Step=480 sec 4.04 MHz ERP = 75 MW O-mode Heater beam (vertical) Spitze direction Field aligned

35 35 SEE

36 36 are weak radio waves produced in the ionosphere by HF pumping. They were originally discovered at HEATING. Stimulated Electromagnetic Emissions HF transmit frequency Gyroharmonic  1.38 MHz in F-layer

37 37 Special effects appear for HF frequencies close to an electron gyro-harmonic. (~1.38 MHz in F-layer) GYRO- HARMONIC

38 38 GYROHARMONIC Artificial aurora 630 nm Cutlass UHF 3 Nov 2000 ERP = 70 MW O-mode

39 39 Artificial HF modulation of Polar Mesospheric Summer Echoes. VHF backscatter power reduces by >40 dB. 10 July MHz ERP = 630 MW X-mode HF off HF on VHF PMSE

40 40 Satellite in the magnetosphere Heating Tx: GW HF wave is amplitude modulated and radiated VLF receiver W ULF/ELF/VLF waves are radiated from the ionosphere 100 km altitude 30 km diameter DC current Ionosphere superimposed ac current Conductivity modulation causes electrojet modulation, which acts as a huge natural antenna ULF ELF VLF waves

41 41 Very Low Frequency waves (kHz) Natural (lightning) and artificial (HEATING) ducted VLF waves resonate with trapped particles in the magnetosphere causing pitch angle scattering and precipitation.

42 42 Ultra Low Frequency waves (3 Hz) Field line tagging

43 43 Artificial Periodic Irregularities (API) The API technique was discovered at SURA and allows any HF pump and ionosonde to probe the ionosphere. API are formed by a standing wave due to interference between the upward radiated wave and its own reflection from the ionosphere. Measured parameters include: N(n), N(e), N(O-), vertical V(i), T(n), T(i) & T(e)

44 44 Further information EISCAT/ SURA

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