Transcript 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.

HEATING
expands the mind
EISCAT training course
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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
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Receiver
The past
N. Tesla (1856-1943)
Tesla
developed
high-frequency
high-power
generators
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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.
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The past
Geometry of
the
Luxembourg
effect
(Tellegen, 1933)
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EISCAT
mainland
EISCAT consists of
much more than just
radars. It possesses
the world‘s largest
high-frequency (HF)
ionospheric
modification facility, called
HEATING or simply
the HEATER.
Built by the MaxPlanck-Society in the
late 1970s, it passed to
EISCAT in 1993.
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A geographic overview of the EISCAT radar, HEATING &
SPEAR HF facilities and CUTLASS coherent scatter radars
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The Heating facility at Tromsø
Control
Antenna 1
Transmitter
Antenna 2
Antenna 3
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Tromsø HEATING facility layout
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HEATER control house with EISCAT radars in the background
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A single HEATING antenna
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An antenna array
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Transmitters
during construction: 6 of 12
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Coax
Only 50 km of home-made
aluminium RF coaxial transmission
lines with mechanical switches
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Thermal expansion: One of many detours
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2 Antennas give
a broad beam
Beam forming
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
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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
overview
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A comparison
HEATING
SPEAR
HAARP (final)
Power (MW): 1.1
0.192
3.3
Antenna
Gain (dB):
16 & 22
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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
Steering:
any
fast
any
fast
ESR
CUTLASS
?
?
KODIAK
Digisonde
24 and 30
only north-south
relatively slow
Diagnostics: KST
CUTLASS
Dynasonde
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The 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
SPEAR
10 MW
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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
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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.
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PLASMA TURBULENCE
12 Nov 2001 5.423 MHz ERP = 830 MW O-mode
UHF
ion line
spectra
HF on
HF off
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PLASMA TURBULENCE
The UHF
radar observes
HF pumpinduced
plasma
turbulence
5.423 MHz
ERP = 1.1 GW
O-mode
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PLASMA 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.
Striations
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HF induced F-region CUTLASS radar backscatter
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Striations
Amplitude of radio waves
received from the satellite
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Striations
After HF pump
off, the
irregularities
decay with time
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HF induced E-region STARE backscatter
(144 MHz)
Tromsø
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Artificially
raised
electron
temperatures
16 Feb 1999
4.04 MHz
ERP = 75 MW
O-mode
Heater on
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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
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HEATER
and UHF
beam
swinging
UHF zenith angle
7 Oct 1999
4.954 MHz
ERP = 100 MW
O-mode
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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
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SEE
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Stimulated Electromagnetic Emissions
HF transmit
frequency
Gyroharmonic  1.38 MHz
in F-layer
are weak radio
waves produced
in the
ionosphere by
HF pumping.
They were
originally
discovered at
HEATING.
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GYROHARMONIC
Special effects appear
for HF frequencies
close to an electron
gyro-harmonic.
(~1.38 MHz in F-layer)
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GYROHARMONIC
3 Nov 2000 ERP = 70 MW O-mode
UHF
Cutlass
Artificial aurora 630 nm
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VHF
HF off
PMSE
Artificial HF modulation of
Polar Mesospheric Summer
Echoes. VHF backscatter power
reduces by >40 dB.
10 July 1999
HF on
5.423 MHz
ERP = 630 MW
X-mode
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Satellite in the magnetosphere
ULF ELF VLF
waves
DC current
100 km altitude superimposed
ac current
Ionosphere
Conductivity modulation causes
electrojet modulation, which acts
as a huge natural antenna
30 km diameter
Heating Tx:
0.2-1 GW HF wave
is amplitude
modulated and
radiated
0.001-1 W ULF/ELF/VLF waves
are radiated from the ionosphere
VLF receiver
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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.
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Ultra Low Frequency waves (3 Hz)
Field line tagging
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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)
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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/
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