Recent results of EMIC/ELF/VLF wave measurements at Athabasca (L=4.2), Canada. Kazuo Shiokawa (ISEE, Nagoya Univ.) Martin Connors (Athabasca Univ.

Size: px

Start display at page:

Download "Recent results of EMIC/ELF/VLF wave measurements at Athabasca (L=4.2), Canada. Kazuo Shiokawa (ISEE, Nagoya Univ.) Martin Connors (Athabasca Univ."

Buddy Waters
5 years ago
Views:

1 Recent results of EMIC/ELF/VLF wave measurements at Athabasca (L=4.2), Canada Kazuo Shiokawa (ISEE, Nagoya Univ.) Martin Connors (Athabasca Univ.)

2 Athabasca (September 3, 2005-) all-sky imager meridian-scanning photometer induction magnetometer Resolute Bay (January 2005-) all-sky imager

3 Athabasca, Canada Sept Sept. 5, 2005

4 Sakaguchi et al. (JGR, 2008)

~khz acceleration/loss Acceleration and loss of radiation belt

5 Radiation Belts electromagnetic ion cyclotron (EMIC) wave: ~Hz loss JAXA Pc5 wave ~mhz acceleration/loss electron cyclotron wave: ~khz acceleration/loss Acceleration and loss of radiation belt (relativistic) electrons by chorus and EMIC waves (Summers et al., 1998)

6 Hβ intensity 30-80keV ions >300keV electrons >800keV electrons >3MeV electrons Miyoshi et al. (GRL, 2008)

7 Statistics of Isolated Proton Aurora midnight Occurrence rate MLT 18MLT Latitudinal Width 00MLT 12MLT 06MLT Sakaguchi et al. (AGU book, 2015) Longitudinal Width

8 Nomura et al. (JGR, 2011)

9 Jun et al. (JGR, 2016) Jun et al. (EPS, 2014)

10 Nomura et al. (JGR, 2016) Ozaki et al. (GRL, 2016)

EMCCD camera (100Hz sampling) Frequency of auroral intensity variation (Hz) Pc1 power frequency (Hz) Auroral intensity (log scale, counts) Pc1 power Intensity (log scale, nt^2) camera

11 EMCCD camera (100Hz sampling) Frequency of auroral intensity variation (Hz) Pc1 power frequency (Hz) Auroral intensity (log scale, counts) Pc1 power Intensity (log scale, nt^2) camera 1-Hz oscillation in both Pc1/EMIC waves and corresponding isolated proton aurora. aurora magnetometer EMIC waves auroral particles waveparticle interactions Time Ozaki et al.(grl, 2018)

12 Radiation Belts electromagnetic ion cyclotron (EMIC) wave: ~Hz loss JAXA Pc5 wave ~mhz acceleration/loss electron cyclotron wave: ~khz acceleration/loss Acceleration and loss of radiation belt (relativistic) electrons by chorus and EMIC waves (Summers et al., 1998)

13 2. Athabasca, Canada induction magnetometer:oct EMCCD camera: since 2014 riometer:oct all-sky airglow camera:since 2005 VLF loop antenna:since 2012

14 Martinez-Calderon et al. (JGR, 2015)

15 Shiokawa et al. (JGR, 2014) 10min

16 VLF/ELF wave statistics at subauroral latitudes (L=4.3) Martinez-Calderon et al. (JGR, 2015)

17 SW speed SW density VLF/ELF wave statistics at subauroral latitudes (L=4.3) (Superposed epoch analysis) SW pressure IMF-Bz AE Dst -5 day +5 day Martinez-Calderon et al. (JGR, 2015)

18 Polarization angle variation of chorus waves time dependent 30-min frequency dependent Martinez-Calderon et al. (EPS, 2015)

19 16 minutes 5 sec 5 sec Rising-tone chorus elements Numerous rising-tone chorus elements Ozaki et al (JGR, 2015)

20 electron cyclotron wave (ELF/VLF wave) Athabasca pulse QP QP emission: +2s or +3s ❶ ❶ ❷ ❷ RBSP QP pulse Pulse: -3s ❶ L=4.3 L=3.65 ❶ ❶ Martinez-Calderon et al. (JGR, 2016)

21 Ground-based stations of the PWING Project. (since May 2016) Existing sites New sites Induction magnetometer Athabasca 60 o 70 o Paratunka Gakona Magadan VLF antenna Kapuskasing 80 o Zhigansk Resolute Eureka Istok (Norilsk) riometer Nain Husafell Kevo Tromsoe EMCCD (100Hz) (ATH, GAK, KEV) MLAT-MLT map Nyrola all-sky camera

22 10min November 6, :00-16:10UT MAM Loop antenna GAK ATH GAK ATH KAP MAM KAP

23 March 30, 2017 KAP ATH KAN Shiokawa et al. (EPS, 2017) 24h

24 Summary We have studied electromagnetic ion cyclotron (EMIC) waves and ELF/VLF (electron cyclotron) waves observed at Athabasca, Canada at L=4.2 at subauroral latitudes. They are related to the acceleration and loss of radiation belt particles. EMIC waves One-to-one correspondence between the EMIC waves and isolated proton auroras This isolated proton aurora is also accompanied by the ~MeV electron precipitation. The EMIC sub-packet structures with a time scale of tens of seconds coincide with the intensity pulsation of the isolated proton auroras in the same time scale. We found ~1-Hz modulation of proton auroral intensity which corresponds to the frequency of the EMIC wave power, suggesting also the modulation of highenergy electron precipitation by the EMIC waves. Magnetospheric ELF/VLF waves Occurrence characteristics of the waves observed at Athabasca statistically using one-year data. We show the first simultaneous observations of the quasi-periodic emissions on the ground and the RBSP-A satellite, and estimated their propagation paths from the magnetosphere to the ground using the observed 2-3 sec timing difference and a ray-tracing model. Based on the simultaneous observations by the PWING stations, we found that these waves tend to be localized in longitudes.

Ground-based network observations for investigation of the inner magnetosphere

Ground-based network observations for investigation of the inner magnetosphere Shiokawa, K. 1, Y. Miyoshi 1, K. Keika 2, M. Connors 3, A. Kadokura 4, T. Nagatsuma 5, N. Nishitani 1, H. Ohya 6, F. Tsuchiya