HEATING expands the mind EISCAT training course

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 100-200 km altitude (the ionosphere) Radio Sender Earth Receiver

The past N. Tesla (1856-1943) Tesla developed high-frequency high-power generators

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.

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

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

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

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

Tromsø HEATING facility layout

HEATER control house with EISCAT radars in the background

A single HEATING antenna

An antenna array

Transmitters during construction: 6 of 12

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

Thermal expansion: One of many detours

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  1100 for high gain antenna

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

A comparison HEATING SPEAR HAARP (final) Power (MW): 1.1 0.192 3.3 Antenna 24 and 30 16 & 22 30 Gain (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 any Steering: relatively slow fast fast Diagnostics: KST ESR ? CUTLASS CUTLASS KODIAK Dynasonde ? Digisonde

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

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

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.

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.

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

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

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

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

HF induced F-region CUTLASS radar backscatter

Striations Amplitude of radio waves received from the satellite

Striations After HF pump off, the irregularities decay with time

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

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

HF pump-induced artificial optical emissions 16 Feb 1999 4.04 MHz ERP = 75 MW O-mode 17:40 HF on 17:44 HF off

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

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: 17.07.50 UT Step=480 sec 4.04 MHz ERP = 75 MW O-mode

SEE

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

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

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

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.

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 0.001-1 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

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.

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

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)

Further information EISCAT/HEATING www.eiscat.uit.no/heater.html HAARP www.haarp.alaska.edu HIPAS www.hipas.alaska.edu ARECIBO www.naic.edu SURA www.nirfi.sci-nnov.ru/english/index2e.html SPEAR www.ion.le.ac.uk/spear/