The search for the acceleration site in a solar flare

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K05397
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Astronomy
• Research Institution: National Astronomical Observatory of Japan
• Principal Investigator: SHIMOJO Masumi 国立天文台, アルマプロジェクト, 准教授 (00332164)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 電波観測 / ミリ波 / ALMA / 太陽フレア / 彩層 / スピキュール

Outline of Final Research Achievements

Solar radio observations with millimeter-wave can reveal not only the physical conditions of the chromosphere but also the behavior of high-energy electrons accelerated in a solar flare. However, solar millimeter-wave observations with a few arc-seconds spatial resolutions had not been done by the difficulties of realizing such observations.
We developed the observing scheme of the Sun with Atacama Large Millimeter/submillimeter Array (ALMA) that is the largest interferometer for observing celestial objects. We succeeded in observing a small solar flare and a spicule, which is a small jet in the chromosphere, with about 2 arc-second resolution using our scheme and deriving the physical parameters of these phenomena from the millimeter data for the first in the world.

Free Research Field

太陽物理学

Academic Significance and Societal Importance of the Research Achievements

ミリ波による高空間分解能での太陽電波観測を実現しただけでなく、ミリ波データによる太陽研究手法を開拓したことが、本研究成果の学術的意義である。ミリ波による太陽研究を今後活発化することにより、太陽の活動現象の理解が深化するだけでなく、現代に生きる我々が多用している地球近辺の宇宙環境の理解も一層深まると思われる。