HAARP-induced Ionospheric Ducts Gennady Milikh, University of Maryland in collaboration with: Dennis Papadopoulos, Chia-Lee Chang, BAEsystems EvgenyMishin, 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 04/24/07 f=3.2 MHz O-mode 0.1 Hz Magn. Zen. No electrojet 10/16/09 f=5.1 MHz, O-mode CW, Magn. Zen.
Kodiak radar diagnostics HF-heating
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.
Demeter observations of the nighttime artificial ducts 04/24/07 f=3.2 MHz O-mode 0.1 Hz Magn. Zen. No electrojet 10/21/09 f=2.8 MHz, O-mode CW, Magn. Zen.
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.
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:
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.
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.
Comparison with the EISCAT experiment (model has been adjusted) The absorption efficiencies=0.16, 0.32 and 0.64.
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.
Comparison with the SURA experiment Absorption efficiencies=0.14 (blue) and 0.25 (red), crosses - observations.
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.
Demeter observations of the nighttime artificial ducts 02/12/10 f=2.8 MHz, O-mode, CW, MZ
The strong signal was detected between 6:30:37 – 6:30:47 shown by arrows
Theory of focusing of HF waves by ducts i.e. forming a focusing lens Expanding n and r by powers of 2 we obtain the focusing distance Lens Magnification:
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.