1Observations of solar radio
bursts using a high-resolution
spectro-polarimeter
Hiroaki Misawa1, Fuminori Tsuchiya1,Kazumasa Iwai2, , Takahiro Obara1, Yuto Katoh3,Shintaro Sato1,4, Kazutaka Kaneda1
and Hirotaka Kashiwagi1
1) Planetary Plasma & Atmospheric Res. Cent., Tohoku Univ., Japan
2) Nobeyama Solar Radio Obs., Nat’l Astron. Obs., Japan
3) Graduate School of Science, Tohoku Univ.
4) Accenture Japan Ltd

Solar Radio Bursts in HF – low UHF band(http://sunbase.nict.go.jp/solar/denpa/hiras/gif/typefignew.gif)

CORONAf ~ fpFLARE
Type-V

SUN

CME

Type-III

Type-II

Plasma density (1/cc)

UHF
VHF

HF
fp=100MHz

fp=10MHz(Type-VI)2(adapted from http://alexeynik.com/images/solar_flare.jpg)

Radial Distance (Rs)

[Want / Aim] Our interestex. SEP & Solar Radio Bursts (Type-II)
Table. Relations between SEP & solar Type-II bursts (1994-2007)(after Gopalswamy+, 2008)

Metric Type-II

Deca~Hectrometric Type-II

Wide band Type-II bursts correlate more closely with SEP.
Fast identification of wide band Type II bursts is effective forearly warning for SEP events.
Importance of wide band radio receiving system  [ Seed ]3

[Seed] Solar Radio Obs. in Tohoku U.

4•July, 2001 Establishment of UHF band 1000m2 radio telescope (IPRT: IitatePlanet. Radio Telescope）
in Fukushima, JapanMiyagi
Fukushima
Fukuoka•Oct. 2010～： Start of VHF～UHF band observation of solar radio spectrausing a new system named “AMATERAS” @150～500MHz•Mar., 2011： Occurrence of the Great East Japan Earthquake → Survived.
•Sept., 2014～： Start of test observation of HF～VHF band observation of solar
radio spectra @(15)～150MHz in Miyagi

[Seed-1] IPRT/AMATERAS

5・IPRT（Iitate Planetary Radio Telescope）
31m
・Feeder: Crossed dipoles with a flat reflector

33m

Antenna type

Offset square parabolas

Phys. aperture1023 m2

Mount

Alt. - Az.

Directional accuracy<0.1°

Reflector

20mm mesh（freq. ＜L-band)[Seed-1] IPRT/AMATERAS (VHF~UHF band) 6・AMATERAS （the Assembly of Metric-band Aperture TElescope and Realtime Analysis System）

Acqiris AC240 ： FFT(after Iwai et al., 2012)

Temporal resolution

10 msec

Freq. resolution

61 KHzFreq. band

150～500 MHz (～0.4Rs)

Polarization

RH & LH (simultaneous)

Min. detectable flux

<0.7 SFU

[Seed-1] IPRT/AMATERAS: Data base
http://pparc.gp.tohoku.ac.jp/data/iprt/＃See also IUGONET→ Meta data search→IPRT→Solar radio data in VHF

7

[Seed-1] IPRT/AMATERAS: Data base
Data name

Low resolution

High resolution

Temporal resolution

1 sec

10 msec

Frequency resolution

1 MHz

61 kHzDynamic range

8 bit (log)8 or 16bit (log)Data size

1.5 MB/h

4.6 or 9.2 GB/h

Data format

FITS

Binary ( FITS)

Availavblity

Download from the web

Contact to Tohoku U.

http://pparc.gp.tohoku.ac.jp/data/iprt/

8[Seed-1] IPRT/AMATERAS：Obs. results
Type-IVZebra(from Hiraiso solar observatory, NiCT)

Type-Iburst(Kaneda+, 2015)

8sec

Type-III

Type-II(Iwai+, 2012;Iwai+,2013,2014)

Type- I
Type-II(Sato+, Kashiwagi+, 2014)

Type-IV？

5sec

Type- I
Type-IV
3sec(Katoh+, 2014)

？

1sec
1sec

9

[Seed-2] new HF～VHF obs. system

10・(15)～150MHz obs. by log-peri. antenna ( future “Array” )2014.9.8

PresentFuture

Observation area: AMATERAS & New(~0.4Rs) (~4Rs)（※Assuming fOBS～fP )Purposes
1. Understandings of fundamental
plasma physics ・・・ particle accel.,
W-P(W) interact.
2. Understandings of phys. of flare,
CME(･SEP) ・・・
generation/propagation env. ～space weather / space disaster sci.

2014/9/28 ~12hJST M5.1 flare
related Type-II burst (linear pol.)GOES X-ray Flux

SDO/AIA094

M5.1 flare

2014/9/28 3hUT

2014/9/28 UT

AMATERAS

Type-II

New System

Type-ⅠΔt=2sec
Δf=30KHz（temporal)

Eliminated band
Eliminated band

Type-Ⅰ

18min

Type-II event
20Summary12［Seed］At present:
VHF~UHF band system for solar radio bursts : AMATERAS
with the resolutions of 10msec & 61KHz (max).
#Data are open and updated everyday.
Near future:
Addition of a new HF~VHF band system (similar resolutions).
［Want (Purpose) & Need］
 Fast & automatic identification of solar radio bursts andevaluation of occurrence of possible hazard (～ SEP) from theirspectral feature (drift rate, frequency range) Collaborative study with modeling / theoretical researches toinvestigate source regions & fundamental physical processes ofsuch hazardous events

1314[Seed-1] IPRT/AMATERAS： Observation stats.
Monthly effective obs. rate (%)
spec.
oper.

equip.
failuresnow>80%
Monthly obvious solar bursts occur. rate (%)

1012
2010

12 3
2011

GOES-Xray

568
2013

10

12

12

4

68
2014

10

12

1
2015

1-8A
1-8A

1-8A
0.5-4A
0.5-4A

0.5-4A

http://www.polarlicht-vorhersage.de/goesSEP : Observer’s positional dependence

15Fig. Heliographic coordinates of CMEs accompanied by Deca-Hectometer type II bursts andthe relation with SEP (>1pfu) in 1994-2007. (Gopalswamy+, 2008)

Sensitivity of the new system

Active sun (burst)
Non Io-DAM

Quiet sun（Thermal）
2 antennas(current)

New system

30 antennas

Fig. Sensitivity the new system with the relation ofnatural radio emissions.

14

Summary & Schedule●Time line
first
２０１３

2nd
２０１４

3rd
２０１５

Test phase
・Develop. of 2stack ant.×3
・Develop. delay line & combiner
・Instal. of high speed specrtometer

4th２０１６5th２０１７6ｔｈ～２０１８～Compl. develop. phase Regular obs.
・Set of 2 stack ant.×10～15
・Insta. of wide-band highspeed spectrometer・Cont. of test obs.

・Obs. starts
・Data open(compl. ver.)Regular obs. with IPRT/AMATERAS●Current status(Mar. 2015）：
・１st antenna, temporal receiver & spectrometer have been installed.
Solar & Jovian radio bursts have been tried to be received.
・Under preparation of 2nd & 3rd antennas & high speed spectrometer23