| Presentation Title: | First Direct Focusing Hard X-ray Imaging of M-Class Solar Flare from FOXSI-4 Sounding Rocket Experiment |
| Author(s): | Shunsaku Nagasawa, Takahiro Minami, Yixian Zhang, Athanasios Pantazides, Kristopher Cooper, Koki Sakuta, Kazuki Ampuku, Ryuto Fujii, Yusuke Yoshida, Riko Shimizu, Yoshiaki Sato, Sota Kashima, Savannah Perez-Piel, Tamar Ervin, Orlando Romeo, Juan Camilo Buitrago-Casas, Juliana Vievering, Wayne Baumgartner, Stephen Bongiorno, Patrick Champey, Steven Christe, Sasha Courtade, Lindsay Glesener, Hunter Kanniainen, Säm Krucker, Juan Carlos Martinez Oliveros, Ikuyuki Mitsuishi, Noriyuki Narukage, Eliad Peretz, Dan Ryan, Shin Watanabe, Tadayuki Takahashi, Mitsuo Oka and FOXSI-4 team |
Abstract:
The Focusing Optics X-ray Solar Imager (FOXSI) is the Solar-dedicated sounding rocket mission to realize the direct imaging method combined with Wolter-I X-ray focusing optics and fine-pitch focal plane detectors. FOXSI has been successfully launched three times so far, in 2012, 2014, and 2018, targetting the quiet Sun, active regions, and microflares. By contrast, the fourth launch, FOXSI-4, was conducted as part of NASA’s first “Flare campaign,” in which the rocket will be kept ready for immediate launch in two weeks to target mid-large class solar flares. To separate thermal and non-thermal emissions, separate intense hard X-ray (HXR) emission from the flaring loop footpoint and weak HXR emission in the corona, and perform photon measurement observations even at high count rates in flares, both focusing optic mirrors and focal plane detectors are upgraded. For the optics modules, new high-resolution optics have been developed by MSFC/NASA and Nagoya University, in addition to the heritage FOXSI-3 10-shell optics. For the focal plane detectors covering the hard X-ray range up to 20 keV, new CdTe double-sided strip detectors (CdTe-DSDs), developed by Kavli IPMU/The University of Tokyo, are installed in four of the seven telescopes, in addition to Si CMOS detectors and a new Timepix3 detector.
On 2024 April 17, FOXSI-4 successfully launched from Poker Flat Research Range/Alaska and obtained the first direct-focusing images of the GOES M1.8 class solar flare. All four CdTe-DSDs successfully acquired data, totaling over 40000 photons in the 4-20 keV range. These data demonstrate the technological readiness of a space-borne mission to observe HXRs from solar flares through direct focusing optics.
We report an introduction to the FOXSI-4 instrument and present the first direct-focusing image of a solar flare, focusing on the HXR range.