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HEATINGHEATINGexpands the mindexpands the mind

EISCAT training courseEISCAT training course

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The pastThe pastG. Marconi (1874 -1937)

Nobel Prize 1909

Earth

There had to be a reflecting layer in order to explain his trans-Atlantic radio wave connection.

Reflecting layer at 100-200 km altitude (the ionosphere)

Radio Sender

Receiver

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Tesla developed high-frequency high-power generators

The pastThe past N. Tesla (1856-1943)

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The pastThe pastAt 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.

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The The pastpast

Geometry of the

Luxembourg effect

(Tellegen, 1933)

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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 EISCAT mainlandmainland

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

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Antenna 1

Antenna 2

Antenna 3

Transmitter

The Heating facility at The Heating facility at TromsøTromsø

Control

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Tromsø HEATING facility layoutTromsø HEATING facility layout

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HEATER control house with EISCAT radars in the background

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A single HEATING antennaA single HEATING antenna

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An antenna arrayAn antenna array

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Transmitters Transmitters during construction: 6 of 12

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Only 50 km of home-madealuminium RF coaxial transmission lines with mechanical switches

CoaxCoax

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Thermal expansion:Thermal expansion: One of many detours

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2 Antennas give a broad beam

4 Antennas give a narrower beamwith more power in the forwarddirection and less power in allother directions.

Effective Radiated PowerEffective Radiated Power = Radiated power Antenna gainAt HeatingAt Heating: 300 MW = 1.1 MW 270 for low gain antennas1.2 GW = 1200 MW = 1.1 MW 1100 for high gain antenna

Beam formingBeam forming

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

World World overviewoverview

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A comparisonA comparisonHEATINGHEATING SPEARSPEAR HAARPHAARP (final)

Power (MW):1.1 0.192 3.3

Antenna 24 and 30 16 & 22 30Gain (dB):

ERP (MW): 300 & 1200 7.6 & 30 3600

Freq. (MHZ): 3.9-5.4 & 5.4-8 2-3 & 4-6 2.8-10

Polarisation: O & X O & X O & X

Beam only north-south any anySteering: relatively slow fast fast

Diagnostics: KST ESR ?CUTLASS CUTLASS KODIAKDynasonde ? Digisonde

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The ionosphereThe ionosphere

Fc = 8.98*sqrt(Ne) for O-mode

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

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A comparison of frequency range and effective radiated power of different facilities

1GW

100 MW

10 MW

SPEAR

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Why do we need the HEATING Why do we need the HEATING facility?facility?

Why?: HF facilities are the only truetrue 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.

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The Incoherent Scatter RadarThe Incoherent Scatter Radar Spectra with Ion and Plasma lines Spectra with Ion and Plasma lines corresponding to ion-acoustic waves and Langmuir wavescorresponding 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 - 2ia,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 = p

2 + e2

The component of the pump electric field perpendicular to the Earth's magnetic field is what matters.

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PLASMA TURBULENCEPLASMA TURBULENCE

HF on

HF off

UHF ion line spectra

12 Nov 2001 5.423 MHz ERP = 830 MW O-mode

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The UHF radar observes HF pump-induced plasma turbulence

5.423 MHzERP = 1.1 GWO-mode

PLASMA TURBULENCEPLASMA TURBULENCE

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PLASMA TURBULENCEPLASMA TURBULENCE

Z-mode penetration

of the ionosphere

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

StriationsStriations

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HF induced F-region CUTLASS radar backscatter

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Amplitude of radio waves received from the satellite

StriationsStriations

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After HF pump off, the irregularities decay with time

StriationsStriations

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Tromsø

HF induced E-region STARE backscatter

(144 MHz)

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Artificially raised electron temperatures

16 Feb 1999

4.04 MHzERP = 75 MWO-mode

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HF pump-induced artificial optical emissions

16 Feb 1999 4.04 MHz ERP = 75 MW O-mode

17:40 HF on17:40 HF on

17:44 HF off17:44 HF off

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HEATER HEATER and and UHF UHF

beam beam swinginswingin

ggUHF zenith angle

7 Oct 1999

4.954 MHz

ERP = 100 MW

O-mode

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ARTIFICIAL AURORAARTIFICIAL AURORA shifted onto magnetic field line

21 Feb 199921 Feb 1999630 nm 630 nm Start time:Start time:17.07.50 UT 17.07.50 UT Step=480 secStep=480 sec4.04 MHzERP = 75 MWO-mode

Heater beam(vertical)

Spitze direction

Field aligned

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SEESEE

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are weak radio waves produced in the ionosphere by HF pumping. They were originally discovered at HEATING.

Stimulated Electromagnetic Stimulated Electromagnetic EmissionsEmissions

HF transmit frequency

Gyroharmonic 1.38 MHz in F-layer

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Special effects appear for HF frequencies close to an electron gyro-harmonic.

(~1.38 MHz in F-layer)

GYRO-GYRO-HARMONICHARMONIC

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GYROHARMONIGYROHARMONICC

Artificial aurora 630 nm

Cutlass

UHF

3 Nov 2000 ERP = 70 MW O-mode

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Artificial HF modulation of Polar Mesospheric Summer Echoes. VHF backscatter power reduces by >40 dB.

10 July 1999

5.423 MHzERP = 630 MWX-mode

HF off

HF on

VHF PMSEPMSE

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Satellite in the magnetosphere

Heating Tx:0.2-1 GW HF waveis amplitude modulated and radiated

VLF receiver

0.001-1 W ULF/ELF/VLF wavesare radiated from the ionosphere

100 km altitude

30 km diameter

DC current Ionosphere

superimposedac current

Conductivity modulation causes electrojet modulation, which acts

as a huge natural antenna

ULF ELF VLF ULF ELF VLF waveswaves

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Very Low Frequency waves Very Low Frequency waves (kHz)(kHz)Natural (lightning) and artificial (HEATING) ducted VLF

waves resonate with trapped particles in the magnetosphere causing pitch angle scattering and precipitation.

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

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Artificial Artificial Periodic Periodic

Irregularities Irregularities (API)(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)

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Further informationFurther information

EISCAT/HEATING www.eiscat.uit.no/heater.htmlHAARP www.haarp.alaska.eduHIPAS www.hipas.alaska.eduARECIBO www.naic.eduSURA www.nirfi.sci-nnov.ru/english/index2e.htmlSPEAR www.ion.le.ac.uk/spear/