HAARP-induced
Ionospheric Ducts
Gennady Milikh, University of Maryland
in collaboration with: Dennis Papadopoulos,
Chia-Lee Chang, BAE systems
Evgeny Mishin, AFRL/RVBXI, Hanscom AFB
Michel Parrot, LPCE/CNRS, France
Joe Huba, NRL
Andrei Demekhov, IAP, N-Novgorod, Russia
Conference on Dynamical Processes in Space Plasma,
Israel, April, 2010
Motivation
• Naturally induced field aligned irregularities of the plasma
density exhibit enhanced refractive indices and act as ducts
that guide waves in the whistler range between the two
hemispheres.
• HF heating of the ionosphere creates density perturbations
that may propagate into the plasmasphere, thus produce
artificial ducts.
Objectives
• To present the observations of the density
perturbations caused by the HF-heating of the
ionosphere by HAARP and detected by Demeter and
DMSP satellites.
• To check the observations against a model of the
artificial ducts due to HF-heating of the ionosphere.
Demeter observations of the daytime artificial ducts
10/16/09
f=5.1 MHz, O-mode
CW, Magn. Zen.
04/24/07
f=3.2 MHz
O-mode
0.1 Hz
Magn. Zen.
No electrojet
4
Kodiak radar diagnostics
HF-heating
5
Daytime Measurements (summarizing)
Daytime artificial ducts are narrow (the width in N-S
direction is under 100 km), and relatively weak (Ni,e and
Ti,e perturbations are under 10%). Thus they can be
detected only from a close overfly.
The artificial ducts required a strong HF-heating which
produces the ionospheric perturbations, such as
observed by Kodiak. To generate such perturbations the
heating frequency should be close to MUF.
8
Demeter observations of the nighttime artificial ducts
10/21/09
f=2.8 MHz, O-mode
CW, Magn. Zen.
04/24/07
f=3.2 MHz
O-mode
0.1 Hz
Magn. Zen.
No electrojet
9
Nighttime Measurements (summarizing)
• Nighttime artificial ducts broader than daytime (the
width reaches 200 km), and Ni,e and Ti,e perturbations
reach 80%. Detectable even at few hundred km
distances from the HAARP MZ.
• Outflow of O+ ions pushes H+ and He+ upward –
artificial polar wind.
12
The model of artificial ducts in the
ionosphere
•It is based on the SAMI2 model of the ionosphere
[Huba, et al., 2000] which describes evolution of the
ionospheric plasma confined by a bunch of the
geomagnetic field lines.
•The SAMI2 model was modified, namely a flexible
local source of the electron HF-heating was introduced
in the form of the localized heating rate per electron:
q   P / Vne  2 10  ( K / s)
4
Model Validation
Validation of the numerical model of ducts
by comparison with two well documented experiments:
The first experiment was conducted at the EISCAT facility and
diagnosed by the EISCAT Incoherent Scatter Radar, which
measured the vertical profiles of the electron and ion
temperature between 150 - 600 km.
The second experiment was conducted at the SURA facility,
and used DEMETER satellite as a diagnostic tool to measure the
ion density along the overflying satellite orbit close to the
magnetic zenith of the HF-heater.
14
EISCAT EXPERIMENT
EISCAT HF facility is located near Tromso, Norway (69oN, 19oE)
Experiments conducted on 10/7/99 [Rietveld et al., JGR, 2003]
Heater operated at 4.5 MHz, ERP=205 MW under quiet
ionospheric conditions.
Major diagnostic tool: UHF ISR.
15
Comparison with the EISCAT experiment (model has been adjusted)
The absorption efficiencies=0.16, 0.32 and 0.64.
16
SURA EXPERIMENT
SURA HF facility located near Nizny Novgorod, Russia (56oN,
46oE).
Experiment conducted on 05/01/06 [Frolov et al., Radiophys. @
Quantum Electronics, 2008] under quiet ionospheric conditions.
The heater operated at 4.3 MHz, O-mode, magnetic zenith,
ERP=80 MW.
Ground-based diagnostics was provided by ionosonde.
17
Comparison with the SURA experiment
Absorption efficiencies=0.14 (blue) and 0.25 (red), crosses - observations.
18
In summary, the modified model of ducts reproduces
observations with high accuracy, which establishes it
as a key tool for the study of the artificial ionospheric
modifications.
19
Demeter observations of the nighttime artificial ducts
02/12/10
f=2.8 MHz, O-mode, CW, MZ
20
Focusing of HF waves by ducts
The strong signal was detected between 6:30:37 – 6:30:47 shown by
arrows
Theory of focusing of HF waves by ducts
2 ΔN
ωe
1
e  0
Δn  
2 ω2 N o
i.e. forming a focusing lens
2
iφo ω
 ω
d ρ
E  Ae
exp i  Δ n dz  r  

2πic
 c
 r
Expanding n and r by powers of 2 we obtain the focusing distance
1

2
ωe  2 ΔNe
zo 
dz

ω2 ρ2 No

2
ρ
zo 
~ 300  400 km if  ~ 50 km
2
Δz ΔN e/No 


ΔN
2
e  ~ 1000
Lens
E/A   f Δz

 2c N
o 
Magnification:






23
Conclusions
•
Artificial ducts due to the ionospheric heating was
detected by the Demeter satellite during daytime &
nighttime.
•
Modified SAMI2 model provides quantitative predictions
of the ducts.
•
HF focusing by ducts propagation was detected. A
theoretical model of HF-focusing was developed.