• Next PPARC Seminar

            PPARC seminar news #04 in FY2017
    2017/5/12(Fri.) 13:00-16:00 at S407 @ C building  chairperson: Kaneda

    Takahiro Obara 小原隆博 (Prof.)

    Hose-collar Aurora and Moving Transpolar Arc

    Hose-collar aurora is one of the manifestation of the sun-aligned polar car arcs for constant IMF By and positive Bz. The narrowed polar cap is associated with bordered morning and evening sides sun-aligned arcs. The horse collar region and the void will be relatively steady phenomenon on a global scale, while there appears an arc forming a single large-scale bar even in the central polar cap. This aurora is known as the theta aurora. The theta aurora is a phenomenon associated with a switch of the IMF By during northward IMF condition. The theta aurora is non-stationary, although the appearance of the arc itself is similar to sun-aligned arcs described above. In this talk we will discuss the formation mechanisms of hose-collar aurora and theta aurora, based on the analyses of numerical MHD simulation results.

    Hiroaki Misawa 三澤浩昭 (Asoc. Prof.)

    Time variable occurrence features of Jupiter's auroral radio emissions - Relation with Io's volcanic variations

    In order to investigate control factor(s) of Jupiter's long & short-term magnetospheric variations, we have investigated occurrence features of Jupiter's auroral radio emission using the radio wave data observed by the WIND satellite for about 20 years. We have derived occurrence variations from the data observed in the frequency range of 0.5 to about 14MHz around Jupiter's occultation periods. The result is controversial & interesting for DAM; i.e., the yearly occurrence probabilities show almost monotonous decrease from 1995 to 2005, then gradual increase after 2005, but after 2009 change to somewhat complex nature with increase and decrease. It does not seem to correspond to variations of De and solar and/or solar wind activities, but implies that some other or multiple causalities control the long term variations. In this study we try to consider the relation between Jupiter's auroral radio activities and Io's volcanic variations using the earth-based optical observation data for Io's volcanic products by Tohoku Univ. and the Hisaki satellite.

    *** PPARC seminar schedule (v1.5, 2017-05-08) ***
    Date, start time, presenters, (chairperson)
    17/04/06(Thu) 13:00- Obara, Sakanoi (Kagitani)
    17/04/10(Mon) 09:00- Mizuguchi (Obara)
    17/04/17(Mon) 09:00- Fukizawa, Ishikawa (Mizuguchi)
    17/04/27(Thu) 13:00- Watanabe, Hirai (Koga)
    17/05/12(Fri) 13:00- Obara, Misawa (Kaneda)
    17/05/20-5/25 JpGU
    17/05/29(Mon) 09:00- presentations of B4-experiments (4) (Tsuchiya)
    17/06/05(Mon) 09:00- Arakawa, Tsuchiya (Kagitani)
    17/06/12(Mon) 09:00- Endo, Sakanoi (Obara)
    17/06/12-16 MOP conference
    17/06/15(Thu) 13:00- Mimura, Koizumi (Mizuguchi)
    17/06/19(Mon) 09:00- Okada, Hino (Kaneda)
    17/07/06(Thu) 13:00- Yagi, Yoshizawa (Misawa)
    17/07/13(Thu) 13:00-> C-seminar
    17/07/14(Fri) 13:00- Kaneda (Misawa)
    17/07/21(Fri) 13:00- Koga, Kagitani (Tsuchiya)

    PPARCセミナーアーカイブ »

    STPPセミナー詳細 »

  • C-Group - Seminar

    **  C-Group Seminar News '17 No.2  **

        ** Topics & Lecture **

    Date & Time : Starting at 13:00 on Thursday, April 13
    Place : Lecture Room #N404

        ** Topics **

    Title: Brief review of ELF/VLF emissions at subauroral latitudes: ground and space observations

    Presenter: Claudia MARTINEZ

    Abstract: Since 2012, continuous measurements of ELF/VLF emissions, have been carried out using a 100-kHz sampling loop antenna at Athabasca (ATH), Canada (54.60N, 246.36E, L=4.3). We used this data to investigate: (1) spectral and polarization characteristics of these waves (2) location of the ionospheric exit point of chorus emissions (3) first statistical analysis of all ELF/VLF emissions observed on the ground at subauroral latitudes (including features, occurrence and association with solar wind parameters). We found maximum occurrence in the morning (06-07 MLT) sector and positive correlation between ongoing substorm/storm activities with increase of wave occurrence.
    In addition, we use conjugate/simultaneous events between RBSP and ATH (same spectral and frequency features) to study wave propagation and generation: (1) QP emission with accompanying short pulse (<1 sec) in the dawn sector (04-06 MLT). We use ray tracing based on plasmaspheric density observed by the spacecraft to validate a propagation scenario. (2) Discrete burst lasting ~3 min at 11:17 UT (03 MLT) associated with strong magnetospheric compression (SI with SYM-H amplitude ~63 nT at ATH). At RBSP-B we also observed a hiss emission starting earlier that was not observed by ATH. We discuss the differences in generation mechanisms and propagation for these two emissions.

        ** Lecture **

    Title: Expectations for Arase (ERG) satellite observation toward further investigation of wave-particle interactions in planetary magnetospheres

    Presenter: Yuto KATOH

    Abstract: The Arase satellite was launched at 20 December 2016 for the exploration of energization and radiation in geospace. One of the prime targets of the Arase satellite is the formation process of radiation belts in the Earth's inner magnetosphere, in which wave-particle interactions between whistler-mode chorus emissions and relativistic electrons play critical roles. Since whistler-mode chorus have been commonly observed in planetary magnetospheres of our solar system, results of investigation by Arase should contribute thorough understanding of wave-particle interactions occurring around other magnetized plantes. In this Lecture we review interactions in the inner magnetosphere mostly focusing on whistler-mode chorus emissions and discuss expectations for the Arase satellite observation.

    *** C-group seminar 2017 schedule (v1.4, 2017-03-31) ***
    17/04/13(Thu) 13:00- Lecture(Kato)
    17/04/20(Thu) 13:00- Poster#1(Fukizawa, Ishikawa, Ishigaya), D-presen(Ohki)
    17/04/23-28 EGU
    17/05/11(Thu) 9:00-17:00 JpGU Rehearsal
    17/05/18(Thu) -
    17/05/20-5/25 JpGU
    17/06/01(Thu) 13:00- Poster#2(Kaneda, Arakawa, Watanabe, Dai, Takenaka, Toyooka), D-presen (Koga)
    17/06/08(Thu) 13:00- Poster#3(Y.Endo, Hirai, Nishida, K.Terada), D-presen
    17/06/12-16 MOP conference
    17/06/15(Thu) -
    17/06/22(Thu) 13:00- Poster#4(Akiba, Kamada, Koizumi, Mimura), D-presen
    17/06/29(Thu) 13:00- D-presen (K.Endo, Mizuguchi)
    17/07/13(Thu) Guest speaker (Prof.Tanaka from astronomical Institute)
    #May-June Bepi-SWT
    #Aug 20-31 IAU
    Poster presen: M1, M2 & D3
    D-presen: Mizuguchi, Koga

    C領域セミナー&アーカイブ »

    PAT - Seminar

    2016/12/2(金) 13:00-
    Naoko Takahashi
    Evolution and propagation of electric fields during magnetospheric disturbances based on multiple spacecraft and ground-based observations

    Kousuke Takami
    Feasibility of the future observations by mid-infrared heterodyne spectroscopy for Wind and Temperature in Venusian mesosphere and lower thermosphere

    PATセミナー詳細 »