T. Hagfors

Publication List Details

Period

1996 - 2009

Number

109

Co-Authors

1 Extremely NarrowBand Stimulated Radio Emissions from the E Region Observed at EISCAT (2009)

V. Belyey, B. Isham, M. T. Rietveld, B. Khudukon, R. Yu. Yurik, E. D. Tereshchenko, ...

Abstract. Stimulated electromagnetic emission (SEE) may occur when the nearEarth space plasma of the ionosphere is subjected to a powerful high frequency (HF, 330 MHz) electromagnetic wave tuned to...

© European Geosciences Union 2005 Dynamic rayed aurora and enhanced ion-acoustic radar echoes (2008)

E. M. Blixt, T. Grydel, N. Ivchenko, T. Hagfors, C. La Hoz, B. S. Lanchester, ...

Abstract. The generation mechanism for naturally enhanced ion-acoustic echoes is still debated. One important issue is how these enhancements are related to auroral activity. All events of enhanced...

© European Geosciences Union 2004 (2008)

T. Grydel, E. M. Blixt, U. P. Løvhaug, T. Hagfors, C. La Hoz, T. S. Trondsen

Interferometric radar observations of filamented structures due to plasma instabilities and their relation to dynamic auroral rays

Strong Langmuir turbulence observed during EISCAT dual-radar high-frequency modification experiments (2007)

Isham Arecibo, B. Isham, C. La Hoz, T. B. Leyser, M. T. Rietveld, T. Hagfors

. A major goal of ionospheric high power radio wave modification experiments is the unraveling of the physics of the plasma turbulence created by the high frequency (HF) pump wave. The signature of...

The relationship between small-scale and large-scale ionospheric electron density irregularities generated by powerful HF electromagnetic waves at high latitudes (2006)

E. D. Tereshchenko, B. Z. Khudukon, M. T. Rietveld, B. Isham, T. Hagfors, A. Brekke

Satellite radio beacons were used in June 2001 to probe the ionosphere modified by a radio beam produced by the EISCAT high-power, high-frequency (HF) transmitter located near Tromsø (Norway)....

The relationship between small-scale and large-scale ionospheric electron density irregularities generated by powerful HF electromagnetic waves at high latitudes (2006)

Tereshchenko, E. D., Khudukon, B. Z., Rietveld, M. T., Isham, B., Hagfors, T., Brekke, A.

Satellite radio beacons were used in June 2001 to probe the ionosphere modified by a radio beam produced by the EISCAT high-power, high-frequency (HF) transmitter located near Tromsø (Norway)....

Directional features of the downshifted peak observed in HF-induced stimulated electromagnetic emission spectra obtained using an interferometer (2006)

Tereshchenko, E. D., Yurik, R. Yu., Khudukon, B. Z., Rietveld, M. T., Isham, B., Belyey, V., ...

A high frequency (HF) ionospheric modification experiment was carried out between 25 September and 8 October 2004, using the EISCAT HF transmitter located near Tromsø, Norway. During this experiment...

The relationship between small-scale and large-scale ionospheric electron density irregularities generated by powerful HF electromagnetic waves at high latitudes (2006)

Tereshchenko, E. D., Khudukon, B. Z., Rietveld, M. T., Isham, B., Hagfors, T., Brekke, A.

Satellite radio beacons were used in June 2001 to probe the ionosphere modified by a radio beam produced by the EISCAT high-power, high-frequency (HF) transmitter located near Tromsø (Norway)....

Directional features of the downshifted peak observed in HF-induced stimulated electromagnetic emission spectra obtained using an interferometer (2006)

Tereshchenko, E. D., Yurik, R. Yu., Khudukon, B. Z., Rietveld, M. T., Isham, B., Belyey, V., ...

A high frequency (HF) ionospheric modification experiment was carried out between 25 September and 8 October 2004, using the EISCAT HF transmitter located near Tromsø, Norway. During this experiment...

Radar soundings of the subsurface of Mars (2005)

Picardi, G., Plaut, J.J., Biccari, D., Bombaci, O., Calabrese, D., Cartacci, M., ...

The martian subsurface has been probed to kilometer depths by the Mars Advanced Radar for Subsurface and Ionospheric Sounding instrument aboard the Mars Express orbiter. Signals penetrate the polar...

DENSITY FLUCTUATIONS IN A PLASMA IN A MAGNETIC FIELD, WITH APPLICATIONS TO THE IONOSPHERE (2005)

HAGFORS, T.

General expressions are developed for the fluctuation in density of electrons, ions, and charge in a plasma in thermal equilibrium in an external magnetic field taking only Coulomb interaction into...

A STUDY OF IONOSPHERIC IRREGULARITIES. (2005)

Boen,H., Christophersen,P., Hagfors,T.

An account is given of theories and experiments designed to investigate the irregular structure of the ionosphere by studying the correlation between radio waves reflected at closely spaced...

An interferometer experiment to explore the aspect angle dependence of stimulated electromagnetic emission spectra (2005)

Isham, B., Hagfors, T., Khudukon, B. Z., Yurik, Yu., Tereshchenko, E. D., Rietveld, M. T., ...

When the Earth's ionosphere is irradiated by a radiofrequency (RF) electromagnetic wave of sufficiently high power density and tuned to match a natural E- or F-region plasma frequency, ionospheric...

Dynamic rayed aurora and enhanced ion-acoustic radar echoes (2005)

Blixt, E. M., Grydeland, T., Ivchenko, N., Hagfors, T., La Hoz, C., Lanchester, B. S., ...

The generation mechanism for naturally enhanced ion-acoustic echoes is still debated. One important issue is how these enhancements are related to auroral activity. All events of enhanced...

An interferometer experiment to explore the aspect angle dependence of stimulated electromagnetic emission spectra (2005)

Isham, B., Hagfors, T., Khudukon, B. Z., Yurik, Yu., Tereshchenko, E. D., Rietveld, M. T., ...

When the Earth's ionosphere is irradiated by a radiofrequency (RF) electromagnetic wave of sufficiently high power density and tuned to match a natural E- or F-region plasma frequency, ionospheric...

Dynamic rayed aurora and enhanced ion-acoustic radar echoes (2005)

Blixt, E. M., Grydeland, T., Ivchenko, N., Hagfors, T., La Hoz, C., Lanchester, B. S., ...

The generation mechanism for naturally enhanced ion-acoustic echoes is still debated. One important issue is how these enhancements are related to auroral activity. All events of enhanced...

Interferometric radar observations of filamented structures due to plasma instabilities and their relation to dynamic auroral rays (2004)

Grydeland, T., Blixt, E. M., Løvhaug, U. P., Hagfors, T., La Hoz, C., Trondsen, T. S.

Several explanations have been proposed for Naturally Enhanced ion-acoustic Echoes observed at mid- and high-latitude Incoherent Scatter observatories. A decisive measure for distinguishing between...

Interferometric radar observations of filamented structures due to plasma instabilities and their relation to dynamic auroral rays (2004)

Grydeland, T., Blixt, E. M., Løvhaug, U. P., Hagfors, T., La Hoz, C., Trondsen, T. S.

Several explanations have been proposed for Naturally Enhanced ion-acoustic Echoes observed at mid- and high-latitude Incoherent Scatter observatories. A decisive measure for distinguishing between...

Performance Comparison of Cross Correlation and Filled Aperture Imaging Riometers. (2003)

Hagfors, T., Grill, M., Honary, F.

In striving for ever greater angular resolution in riometer (relative ionospheric opacity meter) observations it is tempting to try to use a nonfilled array to reduce the cost of antenna elements. We...

A New Imaging Riometer based on Mills Cross Technique (2003)

Grill, M., Honary, F., Nielsen, E., Hagfors, T., Dekoulis, G., Chapman, P., ...

A new type of imaging riometer system based on a Mills Cross antenna array is currently under construction by the Ionosphere and Radio Propagation Group, Department of Communication Systems,...

Novel Fabry-Perot Interferometer Measurements of F-region Ion Temperature. (2003)

Cierpka, K., Kosch, M. J., Holma, H., Kavanagh, A. J., Hagfors, T.

Novel optical measurements of F-region ion temperatures have been made in conjunction with thermospheric neutral temperatures. A ground-based Fabry-Perot interferometer has been used to observe...

High-latitude Pump-induced Optical Emissions for Frequencies Close to the Third Electron Gyro-harmonic (2002)

Kosch, M. J., Rietveld, M. T., Kavanagh, A. J., Davis, C., Yeoman, T. K., Honary, F., ...

It has been long established that high-power O-mode HF pumping of the ionosphere can produce artificial optical emissions. 630 nm O(1D) photons are produced by pump-accelerated electrons colliding...

High-latitude Artificial Aurora Using the EISCAT High-gain HF Facility (2002)

Kosch, M. J., Rietveld, M. T., Kavanagh, A. J., Jussila, J., Isham, B., Kaila, K., ...

The EISCAT high-frequency (HF) transmitter facility at Ramfjord, Norway, has been used to accelerate F-region electrons sufficiently to excite the oxygen atoms and nitrogen molecules, resulting in...

High-resolution Maps of the Characteristic Energy of Precipitating Auroral Particles (2001)

Kosch, M. J., Honary, F., DelPozo, C. F., Marple, S. R., Hagfors, T.

For the first time we produce high-resolution maps of the characteristic energy of precipitating electrons from ground-based instrumentation in the auroral zone over northern Scandinavia. This is...

High Latitude Artificial Aurora from EISCAT: An Unique Phenomenon? (2001)

Kosch, M. J., Rietveld, M. T., Honary, F., Hagfors, T.

The EISCAT HF-facility is capable of transmitting up to 210MW of effective radiated power into the ionosphere around 4 MHz. Beam swinging experiments have been undertaken with O- and X-mode...

High-latitude Ground-based Observations of the Thermospheric Ion-drag Time Constant. (2001)

Kosch, M. J., Cierpka, K., Rietveld, M. T., Hagfors, T., Schlegel, K.

From previous studies, it has been conclusively demonstrated that F-region thermospheric winds follow, but generally lag behind, the ion drift pattern of magnetospheric convection. Analysis of the...

High-latitude HF-induced Airglow Displaced Equatorwards of the Pump Beam. (2000)

Kosch, M. J., Rietveld, M. T., Hagfors, T., Leyser, T. B.

HF-induced airglow at 630 nm was observed by the Digital All-sky Imager, located near Skibotn in Norway, at F-region altitudes above the EISCAT HF facility near Tromsø on 21 February 1999. The...

Ion-neutral coupling in the high-latitude F-layer from incoherent scatter and Fabry-Perot interferometer measurements (2000)

Cierpka, K., Kosch, M. J., Rietveld, M., Schlegel, K., Hagfors, T.

Since the auroral ionosphere provides an important energy sink for the magnetosphere, ionosphere-thermosphere coupling must be investigated when considering the energy budget of the...

Ion-neutral coupling in the high-latitude F-layer from incoherent scatter and Fabry-Perot interferometer measurements (2000)

Cierpka, K., Kosch, M. J., Rietveld, M., Schlegel, K., Hagfors, T.

Since the auroral ionosphere provides an important energy sink for the magnetosphere, ionosphere-thermosphere coupling must be investigated when considering the energy budget of the...

Extrapolating EISCAT Pedersen conductances to other parts of the sky using ground-based TV auroral images (1998)

Kosch, M. J., Hagfors, T., Schlegel, K.

Ionospheric conductivity is not very easily measured directly. Incoherent scatter radars perhaps offer the best method but can only measure at one point in the sky at any one time and are limited in...

Extrapolating EISCAT Pedersen conductances to other parts of the sky using ground-based TV auroral images (1998)

Kosch, M. J., Hagfors, T., Schlegel, K.

Ionospheric conductivity is not very easily measured directly. Incoherent scatter radars perhaps offer the best method but can only measure at one point in the sky at any one time and are limited in...