From Nobeyama to ALMA

Highlights of Nobeyama Solar Results: From Nobeyama to ALMA Kiyoto Shibasaki Nobeyama Solar Radio Observatory 2013/1/15 Solar ALMA WS @ Glasgow 1

Outline Short history Solar physics with radio observations Nobeyama Radioheliograph (NoRH) NoRH / ALMA instruments Science targets of NoRH Particle acceleration, plasma eruption, QS & global lsolar activity it NoRH / ALMA science targets 2013/1/15 Solar ALMA WS @ Glasgow 2

Beginning of solar radio astronomy in Japan 1. The first detection of radio 1 2 3 emission from the Sun (1938) 2. The first 200 MHz dipole antenna array at Mitaka (1949) 3. The first cm wave radiometer at Toyokawa (1951) 4 5 4. The idea of the grating interferometer proposed by M. Oda (1950) 5. The first grating interferometer at Toyokawa (1953) 6 6. Cosmic background measured at Toyokawa (0 ~ 5 K, 1951) Ref: Development of solar radio astronomy in Japan up until 1960 by H. Tanaka, in The early years of Radio Astronomy 2013/1/15 ed. by W. T. Sullivan III, Solar Cambridge ALMA WS @ Glasgow University Press, 1984 3

Nobeyama Radio Polarimeters (NoRP) http://solar.nro.nao.ac.jp/norp/ / / Observing frequencies 1GHz: TYKW/NBYM 1957.3 ~ 2GHz: TYKW/NBYM 1957.6 ~ 375GHz: 3.75 TYKW/NBYM 1951.1111 ~ 9.4 GHz: TYKW/NBYM 1956.5 ~ 17 GHz: NBYM 1978.1 ~ 35 GHz: NBYM (no daily flux values) 80 GHz: NBYM (no daily flux values) (TYKW: Toyokawa, NBYM: Nobeyama) Data acquisition digital data: (0.1 sec) 1987.11 ~ Daily total flux values: 1951.11 ~ Establishment of very robust absolute calibration procedure (Tanaka et al., Solar Phys. 1973) long term solar activity index (daily onthly U) 1 AU Corrected Mo Mean Flux (SFU 450 400 350 300 250 200 150 100 50 0 values around 10 cm are better than relative e sunspot nspotnumbers) 50 studies of high energy particle acceleration in solar flares TYKW(1951 Nov. 1994 Apr.) & NBYM(1994 May 2010 Nov.) 1951 11 1953 11 1955 11 1957 11 1959 11 1961 11 1963 11 1965 11 1967 11 1969 11 1971 11 1973 11 1975 11 1977 11 1979 11 1981 11 1983 11 1985 11 1987 11 1989 11 1991 11 1993 11 1995 11 1997 11 1999 11 2001 11 2003 11 2005 11 2007 11 2009 11 2013/1/15 Solar ALMA WS @ Glasgow 4 9.4GHz 3.75GHz 2.0GHz 1.0GHz

Nobeyama Radioheliograph (NoRH) http://solar.nro.nao.ac.jp/norh/ Specification full disk 17 GHz (I & V) and 34 GHz (I) 1 second cadence 0.1 cadence during flares 10 /5 arcsec (17/34 GHz) res. 84 elements of 80 cm dishes EW: 490 m, NS: 220 m Operation 1992.6 ~ daily 8 hr (Local noon 03UT +/ 4h) Full automaticoperation operation Images around local noon and every 10 min. are on the WEB Studies of Flares (particle acceleration), prominenceeruptions eruptions, umbral oscillation, etc. Studies of QS: Radio butterfly diagram 20 years of daily images (~7000) Long term global solar activity studies (low latitude active regions and high latitude polar brightening) 2013/1/15 Solar ALMA WS @ Glasgow 5

Important questions in solar research Activities on the surface solar flare mechanism and related phenomena such as particle acceleration and plasma heating coronal heating plasma eruptions (CME) Activities inside the Sun magnetic field generation (11/22 year or longer cycles) sunspot generation, active belts, polar field,. Influence to the interplanetary space and the Earth space weather 2013/1/15 Solar ALMA WS @ Glasgow 6

Nature of solar radio emission Bih Bright, extended ddand complex structure Quick change of intensity and structure fast sampling (short integrationtime time, S/Nconsideration) beam size on the Sun / light speed ~ sampling interval Large dynamicrange of intensity variation quick switching of attenuators which introduces phase change Observation during turbulent atmospheric condition phase / amplitude calibration using the sun (self calibration) Large data volume and CPU time simple array configuration and UV plane 2013/1/15 Solar ALMA WS @ Glasgow 7

Solar dedicated radio interferometer (Radio heliograph) Frequency: microwave to study high energy phenomena Receivers: non cooled + attenuator due to large and quickly ikl varying flux Antennas: small antennas and short baselines to cover the whole sun Array: Uniform and dense array to image complex structure quickly 2013/1/15 Solar ALMA WS @ Glasgow 8

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Nobeyama Radioheliograph (NoRH) Radio interferometer dedicated for solar observation Constructed in 1990 19911991 Routine observation since 1992 (20 years) Array configuration: T shape, p, EW:490 m, NS:220m Antennas: 80 cm diameter, EW:56, NS:28 (total 84) Observing frequency: 17 & 34 GHz (λ:1.76cm, 8 mm) Imaging capability bl 1 (Max 10) set of images per second (17 GHz I & V, and 34 GHz I) Full disk image with 10 (5) arc sec. resolution at 17 (34) GHz 8 hours per day without interruption by weather condition (cloud, rain, or snow) 2013/1/15 Solar ALMA WS @ Glasgow 10

Design Principles of NoRH Major science targets studies of particle acceleration in solar flares 17 & 34 GHz (higher than turnover frequency), high cadence (1 or 0.1 sec), full disk Characteristics ofsolarradio radio emission Strong signal and fast variation room temperature receivers (no calibrator sources are available) one bit correlator lt (amplitude independent d correlation) lti Complex sources (extended ~ compact) Dense array: Large flux from an extended disk + sparse array: compact burst components Observing condition is worse due to daytime obs. (turbulent atmosphere) redundant array configuration: self calibration of visibilities The Sun is the calibrator source. Each data set contains calibration data. high quality images of the disk: positional and brightness reference (calibration) Large number of images are needed to study dynamics UV gridding should be avoided due to limited computer power (~20 years ago) 2013/1/15 Solar ALMA WS @ Glasgow 11

NoRH Array Configuration 2013/1/15 Solar ALMA WS @ Glasgow 12

UV Sampling (or Spatial Filter) and Observed Visibility Amplitude 2013/1/15 Solar ALMA WS @ Glasgow 13

Beam Pattern and a Dirty Map 2013/1/15 Solar ALMA WS @ Glasgow 14

Image restoration (CLEAN) 2013/1/15 Solar ALMA WS @ Glasgow 15

Data Archive and Analysis Open data policy All data are online and free to use for research, education and outreach purposes. p Daily images (around local noon 03 UT), 10 min. cadence images, burst images are synthesized and put on the Web page http://solar.nro.nao.ac.jp/index.html /i h l Analysis package (SSW/NORH) (+ user account) is available. Each dataset contains calibration data visibility calibration, position reference, brightness reference Large volume of data analysis can be done by visiting Nobeyama. AIPS or CASA can be used for image synthesis and analysis via C2FITS software. 2013/1/15 Solar ALMA WS @ Glasgow 16

Steady operation 2013/1/15 Solar ALMA WS @ Glasgow 17

Comparison between NoRH and ALMA Nobeyama Radio Heliograph (NoRH) ALMA Number of elements 84 66 Antenna aperture 0.8 m 12m (54), 7m(12, ACA) Max. baseline 05k 0.5km (EW) 2km(100GHz),0.2km(320GHz) 0 (320G ) (without Water Vapor Radiometer) Obs. frequency 17, 34 GHz Band 3 10 (84~950 GHz) Line observation NO YES Circular polarization 17 GHz Band 7 (274 373 GHz) FOV full disk 62 (100GHz), 18 (300GHz) Spatial resolution (FWHM) 10 (17GHz), 5 (34GHz) 0.3 (2km, 100GHz) 0.5 (0.2km, 320GHz) Temporal resolution 1(0.1) sec 32msec (integration time) Observing time 8hr/day, 365day/year, 20years, 99% availability? Calibration self calibration using redundant calibrator source measurements array configuration (every 5 min., solar filter off/on) 2013/1/15 Solar ALMA WS @ Glasgow 18

What we can study with NoRH Emission i Mechanisms at microwave region (incoherent emission from accelerated electrons) 1. Free free emission i electron collision with ions(protons) (thermal electrons) 2. Gyro resonance emission Lower harmonics of cyclotron frequency (thermal electrons + strong magnetic field) 3. Gyro synchrotron emission Higher harmonics ofcyclotronfrequency frequency (non thermal electrons + magnetic field) 2013/1/15 Solar ALMA WS @ Glasgow 19

Sessions and titles of NoRH Review Papers presented at SPRO2012 Nagoya meeting Session 1: Particle acceleration and oscillations in solar flares (GS emission) Two decades of solar flare observations with Nobeyama Radio Heliograph (Masuda) Nobeyama Radioheliograph and Understanding ParticleAcceleration in solar flares (Melnikov) Sausage Oscillations of Flaring Coronal Loops (Nakariakov) Microwave view on particle acceleration in flares (Fleishman) Session 2: Prominence eruptions and interplanetary disturbances (FF emission) Prominence activities observed with Nobeyama Radioheliograph (Shimojo) Interplanetary Disturbances (Gopalswamy) Session 3: Quiet sun, active regions and global solar activity(gr & FF emission) Quiet sun, active regions and global solar activity studied by Nobeyama Radioheliograph (Shibasaki) Solar Predictions using Nobeyama Data (Svalgaard) 2013/1/15 Solar ALMA WS @ Glasgow 20

SESSION 1: PARTICLE ACCELERATION AND OSCILLATIONS IN SOLAR FLARES (GS EMISSION) 2013/1/15 Solar ALMA WS @ Glasgow 21

Flare Morphology(S1, NoRH+Yohkoh) 2013/1/15 Solar ALMA WS @ Glasgow 22

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Dynamics of nonthermal loop 2013/1/15 Solar ALMA WS @ Glasgow 24

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SESSION 2: PROMINENCE ERUPTIONS AND INTERPLANETARY DISTURBANCES (FF EMISSION) 2013/1/15 Solar ALMA WS @ Glasgow 27

Prominence eruption 2013/1/15 Solar ALMA WS @ Glasgow 28

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SESSION 3: QUIET SUN, ACTIVE REGIONS AND GLOBAL SOLAR ACTIVITY(GR & FF EMISSION) 2013/1/15 Solar ALMA WS @ Glasgow 31

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Science Targets of NoRH and ALMA Nobeyama Radio Heliograph (NoRH) ALMA Wavelength Emission mechanisms Cont. / Line Circular pol. FOV Spatial resolution Temporal resolution, continuity, duration short cm ~ mm non thermal / thermal emission g s, g r, f f cont broad spectrum 17 GHz g r, f f f opacity (mag. field) full disk large features (prominence, CH, c l variation), global activities, high chance of event detection (flares, ejections) low large structures 1 (0.1) sec, 8hrs continuous studies of dynamics of larger structure, high h event detection chance, long term activity studies mm ~ sub mm thermal emission f f line / broad spectrum (recombination line above the limb) 320 GHz f f f opacity (kg mag. field patches) small (~ sunspot size) fine structure, less chance of event detection high fine structures (network boundaries, spicules, etc.) 32 msec, broken into 5 min. (calibration), how long? snap shot and slow variation i studies of fine structures 2013/1/15 Solar ALMA WS @ Glasgow 35