Stubbe, P.; Kopka, H.: Stimulated electromagnetic emission in a magnetized plasma: A new symmetric spectral feature. Physical Review Letters 65, pp. 183 - 186 (1990)
Derblom, H.; Thidé, B.; Leyser, T. B.; Nordling, J. A.; Hedberg, Å.; Stubbe, P.; Kopka, H.; Rietveld, M. T.: Tromsø heating experiments: Stimulated emission at HF pump harmonic and subharmonic frequencies. Journal Geophysical Research 94, pp. 10111 - 10120 (1989)
Rietveld, M. T.; Stubbe, P.; Kopka, H.: On the frequency dependence of ELF/VLF waves produced by modulated ionospheric heating. Radio Science 24, pp. 270 - 278 (1989)
Barr, R.; Rietveld, M. T.; Stubbe, P.; Kopka, H.: Ionospheric heater beam scanning: A realistic model of this mobile source of ELF/VLF radiation. Radio Science 23, pp. 379 - 388 (1988)
Wright, J. W.; Kopka, H.; Stubbe, P.: A large-scale ionospheric depletion by intense radio wave heating. Geophysical Research Letters 15, pp. 1531 - 1533 (1988)
Barr, R.; Rietveld, M. T.; Stubbe, P.; Kopka, H.: Ionospheric heater beam scanning: A mobile source of ELF radiation. Radio Science 22, pp. 1073 - 1083 (1987)
Kohl, H.; Kopka, H.; La Hoz, C.; Stubbe, P.: Propagation of artificially excited Langmuir waves in the ionosphere. Radio Science 22, pp. 655 - 661 (1987)
Rietveld, M. T.; Mauelshagen, H.-P.; Stubbe, P.; Kopka, H.; Nielsen, E.: The characteristics of ionospheric heating-produced ELF/VLF waves over 32 hours. Journal Geophysical Research 92, p. 8707 (1987)
Rietveld, M. T.; Stubbe, P.: Ionospheric demodulation of powerful pulsed radio waves: A potential new diagnostics for radars suggested by Tromsø heater results. Radio Science 22, pp. 1084 - 1090 (1987)
Barr, R.; Stubbe, P.; Rietveld, M. T.; Kopka, H.: ELF and VLF signals radiated by the ``Polar Electrojet Antenna'': Experimental results. Journal Geophysical Research 91, pp. 4451 - 4459 (1986)
Barr, R.; Stubbe, P.; Rietveld, M. T.; Kopka, H.: ELF and VLF signals radiated by the "Polar Electrojet Antenna": experimental results. Journal Geophysical Research 91, pp. 4451 - 4459 (1986)
Hanuise, C.; Hedberg, A.; Oksman, J.; Nielsen, E.; Stubbe, P.; Kopka, H.: Comparison between the ionospheric plasma drift and the motion of artificially induced irregularities as observed by HF backscatter radars. Annales Geophysicae 4, p. 49 (1986)
Hedberg, Å.; Derblom, H.; Hamberg, G.; Thidé, B.; Kopka, H.; Stubbe, P.: Measurements of HF backscatter cross section for striations created by ionospheric heating at different power levels. Radio Science 21, pp. 117 - 125 (1986)
The European Space Agency (ESA) has given the green light to build the flight models of the spacecraft and science payload for the PLATO mission to search for extrasolar planets.
In the "Solar and Stellar Interiors" department, Laurent Gizon, Jesper Schou, Aaron Birch, Robert Cameron and others offer PhD projects in solar physics and astrophysics. Helioseismology and asteroseismology are used as important tools to study the oscillating Sun and stars.
The longest-serving solar observatory in space has turned 25 and is still making significant contributions to solar research. Its old age has become an important merit.