Solar Seminar home page (FY2016)

Solar Seminar (13:30-15:00 Monday, Room504 5th floor building 4) Access

News
The next seminar will start from 13:00 on Mar. 6th (Mon).
This is the last seminar of this semester.
We have main talk at 13:00-14:00 and short talk at 14:00-14:30.
And we also have Data Viewing at 14:30-15:00.

Useful webpage list for solar observers.

Next presenters

Date		Name	Title	Abstract	File
3/6	main	K.Namekata
3/6	short	T.Anan
3/6	data viewing	K.Hirose

For Speakers

Presentation time for speaker is: main : 40 minutes as a guide, and 20 minutes discussion.
short : 20 minutes as a guide, and 10 minutes discussion.
Contents of talk are: main : about your study
short : review of recent interesting paper and share information of recent study of the Sun.
Language of slide and talks: Master cource students : Language of slide and talk could be Japanese
Doctor cource students and over : Slide must be English, and talking language could be Japanese
(If those who could not understand Japanese attend the seminar, it is preferable that you talk in English)
Title and Abstract: Please send the title and abstract of your presentation by the day before.
Presentation files: Please upload your presentation files by the start of the seminar.
If the presentation file is very big, please zip the file before uploading.

For Audiences

Honoring speakers: Plase clap your hands as a closure of a presentation to express your respection to a speaker.

For everyone

Publication sharing: Please send a copy of the submitted version of any paper on which they are working to the zasshikai mailing list just after submission

Main speaker
Shibata, Ichimoto, Nagata, Ueno, Asai, Nishida, Isobe, Otsuji, Anan, Ishii,
Kawamura, Takahashi, Tamazawa, Takeshige, Notsu, Hirose, Denis,
Sakaue, Tei, Kou, Nakamura, Namekata, Ninomiya
Short speaker
Tamazawa, Kawamura, Takeshige, Takahashi, Hirose, Denis,
Sakaue, Tei, Kou, Seki, Nakamura, Namekata, Ninomiya
Shibata, Ichimoto, Asai, Ueno, Nagata, Isobe, Ishii, Nishida, Anan, Otsuji

Date		Name	Title	Abstract	File
4/11	---	K.Hirose	Introduction of Solar Seminar		pptx
4/11	main	K.Shibata	Solar Physics in Near Future		pptx
4/18	main	K.Ichimoto	Solar-C and Hida in 2016		pptx
4/25	short	H.Tamazawa
4/25	main	S.Nagata			pptx
5/2	short	A.D.Kawamura	Review on the White House's Action Plan for Space Weather	I will briefly review the action plan of White House of the United States, published Oct. 2015. https://m.whitehouse.gov/sites/default/files/microsites/ostp/final_nationalspaceweatheractionplan_20151028.pdf	pptx
5/2	main	S.Ueno		On 2015-04-27, I introduced several scientific themes of Hida/DST spectroheliograph as a main-talk of the Solar Seminar. But, I think I could not have enough time to introduce themes of CHAIN-project and solar synoptic observation database at that time. So, tomorrow, I would like to talk about "Scientific Themes of CHAIN project and KYOTO Solar Synoptic Observation Image Database".	pdf
5/9	short	S.Takashige		I will review about the paper, "Plasma compression in magnetic reconnection regions in the solar corona, E.Provornikova+, 2016". http://arxiv.org/abs/1604.07325	pptx
5/9	main	A.Asai	Quasi-Periodic Pulsations (QPPs) of H-alpha and white light emission associated with the 2013-May-14 Flare		pptx
5/16	short	T.Takahashi		I will introduce a paper, "magnetic reconnection between a solar filament and nearby coronal loops" as a short talk in the seminar today. The first author is Leping, Li and the paper was published from Naturephysics last week.	pdf
5/2	main	K.Nishida	MHD simulation of large amplitude oscillations in prominence		pptx
5/30	M2 practice	T.Sakaue and A.Tei
6/6	short	K.Hirose		I will introduce the paper below at tomorrow's Solar Seminar. 'The initial trajectories of eruptive solar prominences' (B.P.Filippov, 2016) http://adsabs.harvard.edu/abs/2016ARep...60..356F	pptx
6/6	main	H.Isobe	Probing unresolved physics in reconnection region		pptx
6/13	short	Denis P. Cabezas		I will introduce the paper entitled: "Chromospheric evaporation flows and density changes deduced from Hinode/EIS during an M1.6 flare" by Gomory et al. http://www.aanda.org/articles/aa/pdf/2016/04/aa27403-15.pdf	pdf
6/13	main	K.Otsuji	Current Helicity and Twist of Solar Magnetic Fields from Hinode/SOT SP	Current helicity and twist of solar magnetic fields are important in characterizing the dynamo mechanism working in the convection zone of the Sun. We have carried out a statistical study on the current helicity of solar active regions observed with the spectropolarimeter (SP) of the Hinode Solar Optical Telescope (SOT). We used SOT-SP data of 558 vector magnetograms of a total of 80 active regions obtained during the period from 2006 to 2012. we found a tendency that weak and inclined fields conform to the hemispheric sign rule and strong and vertical fields violate it. These different properties of helicity through the strong and weak magnetic field components give important clues in understanding the solar dynamo as well as the mechanism of formation and evolution of solar active regions.	pptx
6/20	short	T.Sakaue		I will introduce the following paper: "Wave Heating and Range of Stellar Activity in Late-Type Dwarfs" Ulmschneider, P.; Fawzy, D.; Musielak, Z. E.; Stepien, K. ApJ http://adsabs.harvard.edu/abs/2001ApJ...559L.167U This paper is the Letter paper whose full papers are the following: "Acoustic and magnetic wave heating in stars . I. Theoretical chromospheric models and emerging radiative fluxes" http://adsabs.harvard.edu/abs/2002A&A...386..971F "Acoustic and magnetic wave heating in stars . II. On the range of chromospheric activity" http://adsabs.harvard.edu/abs/2002A&A...386..983F "Acoustic and magnetic wave heating in stars . III. The chromospheric emission-magnetic filling factor relation" http://adsabs.harvard.edu/abs/2002A&A...386..994F	pdf
6/20	main	T.Anan	Chromospheric heating and spicule on the network boundaries in the quiet sun	First, I briefly reviewed chromospheric heating studies. Then I present our analysis of IRIS spectra. If I have a time, I will introduce our developing new spectropolarimeter motivated by the chromospheric heating and spicule studies.	pptx
7/4	short	A.Tei			pdf
7/4	main	T.T.Ishii	Observations with Solar Magnetic Activity Research Telescope (SMART) / Solar Dynamics Doppler Imager (SDDI) at Hida Obs., Kyoto-U.	I will introduce observations with SMART/SDDI.	pptx
7/11	short	U.Kou		Today in the short talk I will introduce the following paper Title: Dynamic Hydrogen Ionization Authors: Carlsson, Mats; Stein, R. F. http://adsabs.harvard.edu/abs/2002ApJ...572..626C	pptx
7/11	main	A.D.Kawamura	Why NOAA 12192 did not cause CME? - III
10/17	Data Viewing	K.Otsuji
10/17	short	D.Seki		I will talk about the paper, "Prominence and Filament Eruptions Observed by the Solar Dynamics Observatory: Statistical Properties, Kinematics, and Online Catalog", McCauley et al., 2015/5/26 for today’s Solar Seminar as a short speaker.	pptx
10/17	main	T.Takahashi	Dynamical phenomena associated with coronal shock waves	I will talk about two topics in the seminar. The first topic will be about the interaction between solar prominences and flare associated coronal shock waves. The solar flare is an impulsive release of magnetic field energy stored in the corona. A part of the energy released during flares propagate in the form of MHD fast mode shocks in the corona. The flare associated shock waves sometimes interact with solar prominences, which is the only example of cosmological shock-cloud interaction of human timescale. I will talk about 3D MHD simulation of shock-prominence interaction, and discuss a phenomenological model of prominence acceleration and its applicability to coronal shock/prominence diagnostics. Then, I will talk about emission measure (EM) analysis of coronal shock waves with SDO/AIA data. EM analysis is found to be quite helpful in understanding quantitatively the physical nature of the shock, when applied to coronal shocks observed at the solar limb.	pdf
10/24	Data Viewing	T.Anan		I would like to introduce a high spatial Ha movie of a flare taken by 1.6 m New Solar Telescope at Big Bear Solar Observatory. The movie is the supplementary movie of Jing et al. 2016, Nature Scientific Reports. Please download it from the bellow link, and discuss what can we study by using high resolution data.	avi
10/24	short	T.Nakamura		In today's seminar I will introduce a paper, Kennedy+15. It researches chromospheric heating by non-thermal electron beam after flare occurred in terms of both numerical calculation and observation. URL of Kennedy+15 : http://ads.nao.ac.jp/abs/2015A%26A...578A..72K	pptx
10/24	main	H.Tamazawa		In today's seminar, I will introduce our recent study of Carrington storm with historical document and relation between aurora size and Dst. Because of preliminary study and the matter of license, I do not upload the presentation file in advance.
10/31	Data Viewing	H.Isobe
10/31	short	K.Namekata	Validation of a Scaling Law for the Coronal Magnetic Field Strengths and Loop Lengths of Solar and Stellar Flares
10/31	main	K.Hirose		I am going to talk about my study about filament disappearance and small point-like plasma activation	pptx
11/7	short	S.Ninomiya
11/7	main	Y.Notsu	Spectroscopic observations of active solar-analog stars having high X-ray luminosity, as a proxy of superflare stars	Recent studies of solar-type superflare stars have suggested that even old slowly-rotating stars similar to the Sun can have large starspots and superflares. We conducted high dispersion spectroscopy of 49 nearby solar-analog stars (G-type main sequence stars with Teff = 5,600-6,000 K) identified as ROSAT soft X-ray sources, which are not binary stars on the basis of the previous studies. We expected that these stars can be used as a proxy of bright solar-analog superflare stars, since superflare stars are expected to show strong X-ray luminosity. More than half (37) of the 49 target stars show no evidence of binarity, and atmospheric parameters (temperature, surface gravity, and metallicity) of them are within the range of ordinary solaranalog stars. We measured the intensity of Ca II 8542 and H lines, which are good indicators of the stellar chromospheric activity. The intensity of these lines indicates that all the target stars have large starspots. We also measured v sin i (projected rotational velocity) and Lithium abundance for the target stars. Li abundance is a key to understand the evolution of the stellar convection zone, which reflects the stellar age, mass and the rotational history. We confirmed that many of the target stars rapidly rotate and have high Li abundance, compared with the Sun, as suggested by many previous studies. There are, however, also some target stars that rotate slowly (v sin i = 2-3 km s-1) and have low Li abundance like the Sun. These results support that old and slowly-rotating stars similar to the Sun could have high activity level and large starspots. This is consistent with the results of our previous studies of solar-type superflare stars. In the future, it is important to conduct long-term monitoring observations of these active solar-analog stars in order to investigate the detailed properties of large starspots from the viewpoint of stellar dynamo theory.	pdf
11/14	guest talk	Dr. Jeongwoo Lee	Study of solar flares inside a large magnetic fan structure with NoRH observations	Understanding how solar eruption proceeds is an important step toward the ultimate goal of solar physics and space weather forecast. Although the exact mechanisms for solar eruptions are still under debate, it is generally believed that the key information lies in the characteristic magnetic configuration of source active regions. In this talk I will present an on-going study of two successive solar flares from NOAA AR 12371 that occurred on 2015 June 21. The photospheric magnetograms and coronal EUV images from the Solar Dynamic Observatory (SDO) imply that the active region consists of two sunspots embedded within a strikingly large magnetic fan structure. It is therefore of new interest how the compact sunspot fields were interacting with the extended overlying magnetic structure to produce the such successive flares, one associated with a sigmoid structure and the other, with a halo CME. We analyze the unique dataset from the Nobeyama Radioheliograph (NoRH) operated by Nagoya University to derive information on the primary energy release and high energy particles accelerated during the two flares. While the solar EUV images show a continuous change of the coronal features, the NoRH detected two well separated (>25 min) radio bursts with distinct properties of both spectral and spatial morphologies. We relate the former radio bursts to an impulsive energy release within a confined magnetic structure and the latter to the aftermath of the CME. Our ultimate goal is to figure out the magnetic connectivity change that is responsible for the transition from the confined flare to the eruptive flare within 40 min time interval
12/5	Data Viewing	K.Nishida
12/5	short	K.Shibata			pdf
12/5	short	S.Ueno			pdf
12/12	D2 presentation	S.Takeshige
12/19	main	Denis			pdf
12/19	short	S.Nagata
12/19	Data Viewing	A.D.Kawamura
12/26	main	T.Nakamura			pptx
12/26	Data Viewing	T.T.Ishii
1/16	main	S.Ninomiya
1/23	short	K.Ichimoto			pdf xlsx
1/23	short	A.Asai
1/23	short	A.D.Kawamura
1/30	practice of M2 presentation	U.Kou
1/31	practice of M2 presentation	A.Tei, U.Kou and T.Sakaue
2/6	Guest talk	S.Yashiro
2/13	Guest talk	A.Ibrahim
2/27	main	D.Seki	3 characteristic features of line-of-sight velocity of a filament as the precursor of filament eruptions	Filaments, the dense cooler plasmas in the solar corona, often become unstable and erupt into the interplanetary space as coronal mass ejections (CMEs). The CMEs may cause geomagnetic storms that result in various societal and economical impacts such as blackouts and satellite anomalies, so that it is important to predict when filament eruptions will occur. The aim of this study is to investigate the characteristics of eruptive filaments that can be used as the precursor of eruptions. For this purpose, we analyzed the solar full disk images captured by Solar Dynamics Doppler Imager(SDDI) installed on Solar Magnetic Activity Research Telescope(SMART) at Hida Obser- vatory, Kyoto University. SDDI can obtain solar full disk images in 73 wavelengths between Ha center-9A and Ha center+9A per 0.25A with the time resolution of about 15 seconds. Therefore this instrument can observe unprecedented detailed line-of-sight velocities of filaments. Focusing on this feature, the filament’s line-of sight velocities for each pixel of the images by utilizing Beckers’ cloud model was calculated and 3 features were found : 1. Increase in the amplitude of line-of-sight velocity of the filament's small scale motion 2. Increase in the oscillation amplitude of the global filament’s motion 3. a mysterious downward motion and trigger for a filament eruption In this talk, I will introduce these 3 features and discuss the possibility for the prediction of filament eruptions.
2/27	short	K.Nishida	UNIFIED MODEL OF DURATIONS OF LONG DURATION EVENTS AND IMPULSIVE FLARES	We investigated the factors determining the durations of solar flares. By numerical simulation, we attempted to explain the durations of both long-duration events (LDEs) and impulsive flares using a unified model. By carrying out 2.5D magnetohydrodynamic (MHD) simulations of flares with a flux rope eruption, we investigated the dependence of the duration on the size of the inflow region, while changing the magnetic configurations of quadrupolar loops under the flux rope in the initial conditions. The duration changed with the size of the inflow region, and we found a linear correlation between them.
2/27	Data Viewing	T.Sakaue