Blar i forfatter "Kosch, Michael J."

Viser treff 1-6 av 6

    • Aspect angle sensitivity of pump-induced optical emissions at EISCAT 

      Kosch, Michael J.; Bryers, Carl; Rietveld, Michael T; Yeoman, Timothy K; Ogawa, Yasunobu (Journal article; Tidsskriftartikkel; Peer reviewed, 2014-12-04)
      We investigate the aspect angle sensitivity of the pump-induced artificial optical emissions in the ionosphere over the European Incoherent Scatter Scientific Association (EISCAT) high-frequency transmitter facility at Ramfjord, Norway, as a function of the pump beam launch angle relative to the magnetic field line direction. The highest intensity optical emissions occur when the pump beam pointing ...

    • A comparison of overshoot modelling with observations of polar mesospheric summer echoes at radar frequencies of 56 and 224 MHz 

      Havnes, Ove; Pinedo Nava, Henry; La Hoz, Cesar; Senior, Andrew; Hartquist, Thomas W.; Rietveld, Michael T; Kosch, Michael J. (Journal article; Tidsskriftartikkel; Peer reviewed, 2015)
      We have compared radar observations of polar mesospheric summer echoes (PMSEs) modulated by artificial electron heating, at frequencies of 224 MHz (EISCAT VHF) and 56 MHz (MORRO). We have concentrated on 1 day of observation, lasting ~ 3.8 h. The MORRO radar, with its much wider beam, observes one or more PMSE layers all the time while the VHF radar observes PMSEs in 69% of the time. Statistically ...

    • A New Technique for Investigating Dust Charging in the PMSE Source Region 

      Mahmoudian, Alireza; Kosch, Michael J.; Vierinen, Juha; Rietveld, Michael T (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-09-21)
      A new technique for investigating dust charging in the PMSE (polar mesospheric summer echoes) source region is proposed and discussed in this paper. The first high-frequency (HF) modulation of the PMSE with varying pump power was employed during a recent experimental campaign at EISCAT (European Incoherent Scatter Scientific Association). Two experiment setups including HF pump power stepping as ...

    • Stimulated Brillouin scattering during electron gyro-harmonic heating at EISCAT 

      Fu, Haiyang; Scales, Wayne A.; Bernhardt, Paul A.; Briczinski, Stan J.; Kosch, Michael J.; Senior, Andrew; Rietveld, Michael T; Yeoman, Timothy Kenneth; Ruohoniemi, J. Michael (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-08-11)
      Observations of secondary radiation, stimulated electromagnetic emission (SEE), produced during ionospheric modification experiments using ground-based, high-power, high-frequency (HF) radio waves are considered. The High Frequency Active Auroral Research Program (HAARP) facility is capable of generating narrowband SEE in the form of stimulated Brillouin scatter (SBS) and stimulated ion Bernstein ...

    • SuperDARN radar-derived HF radio attenuation during the September 2017 solar proton events 

      Bland, Emma; Heino, Erkka Petteri; Kosch, Michael J.; Partamies, Noora (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-08-10)
      Two solar proton events in September 2017 had a significant impact on the operation of the Super Dual Auroral Radar Network (SuperDARN), a global network of high‐frequency (HF) radars designed for observing F region ionospheric plasma convection. Strong polar cap absorption caused near‐total loss of radar backscatter, which prevented the primary SuperDARN data products from being determined for a ...

    • Survey of conditions for artificial aurora experiments at EISCAT Tromsø using dynasonde data 

      Tsuda, T. T.; Rietveld, Michael T; Kosch, Michael J.; Oyama, S; Hosokawa, K.; Nozawa, Satonori; Kawabata, T; Mizuno, A; Ogawa, Y (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-02-14)
      We report a brief survey on conditions for artificial aurora optical experiments in F region heating with O-mode at the EISCAT Tromsø site using dynasonde data from 2000 to 2017. The results obtained in our survey indicate the following: The possible conditions for conducting artificial aurora experiments are concentrated in twilight hours in both evening and morning, compared with late-night hours; ...