Hessdalen
2002 - I.C.P.H. Mission Update:
Analogies and Speculation
Flavio
Gori
gori@mail630.gsfc.nasa.gov
It
is known that Very low frequency (VLF) waves, which have
frequency in the radio range 3-30 kHz, are emitted, between
other sources, by natural phenomena earth and space based
connected through the atmosphere and by very powerful
man-made VLF transmitters. In the last twenty years did
arise the capability to generate VLF/ELF waves using
powerful ground based HF (High Frequency) radar. This is to
modulate the intense auroral electroject currents that flow
in the D and E ionospheric regions, causing natural currents
to radiate ELF/VLF waves from an altitude range of 70/100
km, though these altitude are strictly depending upon the HF
frequency used (6). A number of such experiments were
carried out near the Norwegian town of Tromsø, around
700 km north/west from the Hessdalen valley, during the
1980-1990 and beyond years (6a).
Below
we list the most important features of these experiments, as
shown in the PARS Project article by Inan and Bell at Star
Lab, Stanford University (6a):
1)
The Tromsø HF ionospheric heating facility
successfully produced electromagnetic waves in the 200 Hz
to 6.5 kHz frequency range with an amplitude of
approximately 1 pT as measured on the ground. The ELF/VLF
wave amplitude was roughly constant between 2&endash;6
kHz, but dropped by 3 dB at the lower end of the
frequency range.
2)
The HF heater frequency generally lay within the three
frequency bands: 2.75 - 4 MHz, 3.85 - 5.6 MHz, and 5.5 -
8 MHz, and the HF signal was generally 100% amplitude
modulated with a square wave.
3)
The HF radiated power was approximately 1 MW, and the
effective radiated power (ERP) generally lay in the range
of 200 to 300 MW.
4)
It was generally found that X-mode polarization of the HF
signal resulted in a more intense radiated ELF/VLF signal
than O-mode polarization.
5)
The ELF/VLF signal strength was highly correlated with
magnetic activity, and significantly more intense ELF/VLF
waves were produced during periods of moderate
geomagnetic disturbance with Kp~ 3.
6)
The amplitude of the ELF waves was essentially
independent of the ERP of the HF signal, but depended
only on the total HF power delivered to the
ionosphere.
7)
The ratio of heating to cooling time constants ranged
from 1 at 510 Hz to 0.3 at 6 kHz.
The
Tromsø facility was also used to excite ULF waves in
the 1.67 - 700 mHz frequency range [Stubbe and
Kopka, 1981; Stubbe et al., 1985; Maul et
al., 1990]. A variety of HF modulation schemes were
attempted. The amplitude of the excited ULF waves were of
the order of 100 - 10,000 pT (6a).
Once
the VLF waves are sent out, they travel up through the
ionosphere to the Earth's magnetosphere. Because of this
disturbance, they cause many natural emissions such as
Whistlers, waves in the audio range. The electrons caught in
the Whistlers spiral along the lines of force in the Earth's
magnetic field until they reach the opposite hemisphere, in
the magnetic conjugate point. When they reach the magnetic
pole and hit the Earth's atmosphere, they precipitate into
the atmosphere. This phenomenon of electron precipitation
causes the aurora borealis or Northern Lights.
Physical
Data Analogies
Northern Lights are an astonish natural phenomena, showing a
number of colors in the atmosphere, at about the same
geographical and magnetical coordinates than the Hessdalen
valley, worldwide. But we are experiencing Hessdalen
Phenomena just in that Norwegian area. Moreover Northern
Lights appear to be a slow motion or even an almost still
phenomena, facing the very fast changing and moving
Hessdalen Lights. A pretty different phenomena, it is well
known. Anyway composition or triggering causes might have
something to share.
In
this perspective we should take in account the ongoing
influence of a high speed solar wind stream I.M.F. in order
to understand the eventually Bz based influence in the
Hessdalen area. Not only.
Following information from the Valley as well statistical
studies (1a), data from observations in the Hessdalen
Valley refer about a fall-winter time as the higher
sightings season (months around the Winter Solstice). In
particular it seems involve October to February as the most
important sightings season, while the June to July, maybe
first August week too, as the minor one (months around the
Summer Solstice). Beside it may be due to the most dark and
light seasons through the year in that northern State (15),
these two times appear to be in good accord, even the
peak-time during the day, around midnight (1-1a-3-15), with
Electron Density through the seasons in the
Ionospheric F layer and beyond, the Plasmasphere.
In
the October-March season, according the reported sources, we
measure the highest electron density for cubic meter with a
peak in the beginning of January. In the June to July season
we experienced the lowest density rate.
These
data did appear since the R.A. Helliwell at Stanford
University observations in the '60s (7) as shown in various
sources (9-14-16), though it is not possible collecting
electronic density data just over the Hessdalen area,
lacking any Observatory. For this purpose we have used the
Ny Alesund Observatory, though far North from Hessdalen
(11.8700 East; 78.9200 North), it is the only Norwegian
Electron Observatory available for report through time.
Though the F layers is the highest ionospheric region and
Plasmasphere is even higher, a strong electric field builds
up on the ground, whose polarity is most often such that it
pushes the F layer aside, allows energetic electrons from
the higher ionospheric layers to penetrate to lower levels.
This may recall the very high electricity reported in the
very low atmosphere, during all the EMBLA Missions
(1&endash;2 and 2b), as well as L.E.P. phenomena (11-12)
and, on the other hand, the Whistler propagation path (7),
reaching the lower atmospheric layers and the ground itself.
Electrical ducts can actually push downward particles as
well.
In
the PARS Project, Authors Inan and Bell (StarLab at Stanford
University) proposing a possible accompanying ionospheric
effects due to induced precipitation of energetic electrons,
generated by HAARP HF emissions, able to stimulate ELF/VLF
signals as well as such ionospheric effects (6a). So manmade
activity may excite (though unexpected) the needed overall
condition in ionosphere and atmosphere, to get the one
usually created by nature, to induce higher electron
temperature and precipitation of energetic electrons toward
the lower ionospheric as well as atmospheric
layers.
This
situation may induce electron fluctuations, able to produce
most favorable condition to trigger optical phenomena in the
low atmosphere, breaking SCEBs, with no (or partial) need of
natural seasonal connections.
References
1)
EMBLA 2001 : THE OPTICAL MISSION, by Massimo Teodorani,
Erling Strand and Bjørn Gitle Hauge.)
http://www.itacomm.net/PH/,
(October 2001);
1a)
ANALISI dei DATI di FENOMENI LUMINOSI ANOMALI a HESSDALEN,
by M. Teodorani and E. Strand; http://www.itacomm.net/PH
(2000);
2)
EMBLA 2001: VLF RADIO REPORT, by Flavio Gori
http://www.loscrittoio.it/Pages/FG-1201.html
and http://www.itacomm.net/PH
, (December 2001);
2a) A VLF/ELF proposal for on the field research at
Hessdalen, by Flavio Gori, Proceeding Hessdalen Project at
Medicina (May 1999);
3)
EMBLA_2002: AN OPTICAL AND GROUND SURVEY IN HESSDALEN, by
Massimo Teodorani and Gloria Nobili. http://www.hessdalen.org/reports/EMBLA_2002_2.pdf,
(0ctober 2002);
4)
PROJECT HESSDALEN, by Erling Strand http://www.hessdalen.org/reports/ProjectHessdalen-story-April2002.pdf,
(April 2002);
5)
HESSDALEN IS A NORWEGIAN VALLEY, by Flavio Gori
http://www.loscrittoio.it/Pages/FG-0901.html
and http://www.itacomm.net/PH,
(September 2001);
6)
VLF INTERFEROMETRY, By Umran S. Inan, STAR Lab at Stanford
University (June 2001) http://www-star.stanford.edu/~vlf/interferometry/VLFinfer.html
6a)
POLAR AERONOMY AND RADIO SCIENCE (PARS)
ULF/ELF/VLF PROJECT by U. S. Inan and T. F. Bell from
STAR Laboratory, Stanford University
http://www-star.stanford.edu/~vlf/pars/pars.htm#A.2%20Troms%20Experiments
7)
WHISTLERS AND RELATED PHENOMENA, by R.A.
Helliwell:, Stanford University Press 1965.
8)
ESA SPACE SCIENCE DEPARTMENT, Noordwijk, The
Netherlands
9)
USING GPS TO MONITOR IONOSPHERIC IRREGULARITIES IN THE
SOUTHERN HIGHLATITUDE REGION by Yue-Jin Wang, P. Wilkinson
and J. Caruana (1997), IPS Radio and Space Services
(Australia)
10)
ON THE FIELD REPORT by Matteo Leone (2003), under
development
11)
LIGHTNING-INDUCED ELECTRON PRECIPITATION
H. D. Voss*, W. L. Imhof*, M. Walt*, J. Mobilia*, E. E.
Gaines*, J. B. Reagan*, U. S. Inan**, R. A. Helliwell*, D.
L. Carpenter**, J. P. Katsufrakis** & H. C. Chang**
* Lockheed Palo Alto Research Laboratory, Palo Alto,
California 94303. USA ** STAR Laboratory, Stanford
University, California 94305, USA
20 December 1984 © Macmillan Journals Ltd..
1985
12)
SATELLITE OBSERVATIONS OF LIGHTNING-INDUCED ELECTRON
PRECIPITATION
H. D. Voss, M. Walt, W. L. Imhof, J. Mobilia, and U. S.
Inan
1. Taylor University, Upland, IN
2. STAR Laboratory, Stanford University, Stanford, CA
94305
13)
A COMPARISON STUDY OF THE AURORAL LOWER THERMOSPHERIC
NEUTRAL WINDS DERIVED BY THE EISCAT UHF RADAR AND THE
TROMSØ MEDIUM FREQUENCY RADAR
S. Nozawa,1 A. Brekke,2 A. Manson,3 C. M. Hall,2 C.
Meek3 K. Morise,1 S. Oyama,4 K. Dobashi,5 and R. Fujii1
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 107, NO. A8,
10.1029/2000JA007581, 2002
14)
THE ELECTRON DENSITY DISTRIBUTION IN THE POLAR CAP:
ITS VARIABILITY WITH SEASONS, AND ITS RESPONSE TO MAGNETIC
ACTIVITY
Harri Laakso and Réjean Grard
ESA SPACE SCIENCE DEPARTMENT, NOORDWIJK, THE
NETHERLANDS
15)
HESSDALEN: TECHNICAL REPORT, by Erling Strand, 1984
http://www.hessdalen.org;
16)
SPACE WEATHER WEB - Facilities for Radio Communications
Users Vertical TEC across Scandinavia for the last 24 hours
http://ionosphere.rcru.rl.ac.uk/scandinavia.html.
Aknowledge
Renzo
Cabassi and ICPH/CIPH (Italian Commitee for
Projetc Hessdalen or Comitato Italiano per il Progetto
Hessdalen), for their friendship, assistance and
financial support to let me be in Hessdalen;
Matteo
Leone a very friendly mate and great on the field
researcher;
Stelio
Montebugnoli for his UHF radar and very precious
advises;
Gloria
Nobili and Massimo Teodorani for their
scientific discussion and advises;
Marsha
Adams of Times Research Inc., a great
researcher, involved in a lot of fields: VLF, chemical,
optics and radon;
Erling
Strand, leader of Hessdalen Project,
for the informations he gave me during my days in the
valley and during data analysis.
Luciano
Cianchi, Luigi Ciraolo and Paolo Moretti, all
from CNR-IROE-Firenze; as well as Cesare
Tagliabue, I5TGC; for their scientific support before
and after my Hessdalen times;
Dennis
Gallagher from NASA Marshall Space
Flight Center for his scientific
advises;
William
Taylor and William Pine from
NASA-INSPIRE Project, Goddard Space
Flight Center for their scientifical assistance
during data analysis;
Stanislav
Klimov, I.K.I., Russian Space Research Institute, for
his scientific advises;
Peder
and Sig Skogaas for their lovely friendship and
important help to coordinate our work with the
inhabitants, a very important item;
Jonathan
Tisdall AFTENPOSTEN daily Journalist,
for his help in find out news about the valley and
Norway;
Ellin
with Birger Brattas and Bjiorne with
Hallfrid Lillevold, Ruth Mary Moe with her
daughter Randi, Hessdalen valley residents, for
giving us so many informations about lights in the valley
and how inhabitants feel about, even in the previous
times.
All the norwegian people greeting us during our time
in the valley.
©
Copyright (2003) Flavio Gori
(LoScrittoio.it)
© Copyright (2003) CIPH
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