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HEATING expands the mind

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Presentation on theme: "HEATING expands the mind"— Presentation transcript:

1 HEATING expands the mind
EISCAT training course

2 The past G. Marconi (1874 -1937) Nobel Prize 1909
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 Earth Receiver

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

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

6 EISCAT consists of much more than just radars
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 1993. EISCAT mainland

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

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

9 Tromsø HEATING facility layout

10 HEATER control house with EISCAT radars in the background

11 A single HEATING antenna

12 An antenna array

13 Transmitters during construction: 6 of 12

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

15 Thermal expansion: One of many detours

16 Beam forming 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 = Radiated power  Antenna gain At Heating: 300 MW = 1.1 MW  270 for low gain antennas 1.2 GW = 1200 MW = 1.1 MW  for high gain antenna

17 World overview 1970: Platteville, Colorado
1975: SURA (Nizhni Novgorod), Russia ~1980: Arecibo (Puerto Rico), Tromsø (Norway), HIPAS (Alaska) 1995: HAARP (Alaska) 2003: SPEAR (Svalbard) World overview

18 A comparison HEATING SPEAR HAARP (final) Power (MW): 1.1 0.192 3.3
Antenna 24 and & Gain (dB): ERP (MW): 300 & & Freq. (MHZ): & & Polarisation: O & X O & X O & X Beam only north-south any any Steering: relatively slow fast fast Diagnostics: KST ESR ? CUTLASS CUTLASS KODIAK Dynasonde ? Digisonde

19 The ionosphere Fc = 8.98*sqrt(Ne) for O-mode
Fc = 8.98*sqrt(Ne) + 0.5*Be/m for X-mode

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

21 Why do we need the HEATING facility?
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 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(0 - 2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: 02 = p2 + e2 The component of the pump electric field perpendicular to the Earth's magnetic field is what matters.

23 PLASMA TURBULENCE 12 Nov 2001 5.423 MHz ERP = 830 MW O-mode
UHF ion line spectra HF on HF off

24 PLASMA TURBULENCE The UHF radar observes HF pump-induced plasma turbulence 5.423 MHz ERP = 1.1 GW O-mode

25 Z-mode penetration of the ionosphere
PLASMA TURBULENCE Z-mode penetration of the ionosphere

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 HF induced F-region CUTLASS radar backscatter

28 Striations Amplitude of radio waves received from the satellite

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

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

31 Artificially raised electron temperatures
16 Feb 1999 4.04 MHz ERP = 75 MW O-mode Heater on

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

33 HEATER and UHF beam swinging
UHF zenith angle 7 Oct 1999 4.954 MHz ERP = 100 MW O-mode

34 shifted onto magnetic field line
ARTIFICIAL AURORA shifted onto magnetic field line Heater beam (vertical) Spitze direction Field aligned 21 Feb 1999 630 nm Start time: UT Step=480 sec 4.04 MHz ERP = 75 MW O-mode

35 SEE

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

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

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

39 VHF PMSE Artificial HF modulation of Polar Mesospheric Summer Echoes. VHF backscatter power reduces by >40 dB. 10 July 1999 5.423 MHz ERP = 630 MW X-mode HF off HF on Negatively charged aerosols, I.e. ice particles or cluster ions, prevent electron diffusion from equalising electron irregularity structures in the mesopshere, which cause strong coherent echoes, I.e. PMSE. Increasing electron temperature compensates the effect of negatively charged aerosols on the diffusion of electrons. Increasing Te enhances electron diffusion and destroys PMSE.

40 ULF ELF VLF waves Satellite in the magnetosphere Ionosphere DC current
Conductivity modulation causes electrojet modulation, which acts as a huge natural antenna 100 km altitude 30 km diameter superimposed ac current W ULF/ELF/VLF waves are radiated from the ionosphere Heating Tx: 0.2-1 GW HF wave is amplitude modulated and radiated VLF receiver

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

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 Further information EISCAT/HEATING

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