Automated solar radio burst detection on radio spectrum: a review of techniques in image processing

The information of solar atmosphere was obtained after investigating the recording radiation of the space mission. With technology growing recently, a lot of solar radio receiver was introduced to monitor the solar radio activity on the ground with high efficiency. It is recorded in every second for 24 hours per day. A massive of solar radio spectra data produced every day that makes it impossible to identify, whether the data contain burst or not. By doing manual detection, human effort and error become the issues when the solar astronomer needs the fast and accurate result. Recently, the success of various techniques in image processing to identify solar radio burst automatically was presented. This paper reviews previous technique in image processing. This discussion will help the solar astronomer to find the best technique in pre-processing before moving into the next stage for detection of solar radio burst.Keywords: monitoring solar activity; automated solar radio burst detection; image processing; techniqu

A comparative study of measured amplitude and phase perturbations of VLF and LF radio signals induced by solar flares

Very Low Frequency, VLF and Low Frequency, LF signal perturbations were examined to study ionospheric disturbances induced by solar X-ray flares. The aim was to understand processes in propagation VLF/LF radio signals over short paths, and to estimate specific characteristics of each short path. The receiver at Belgrade station continuously monitor the amplitude and phase of coherent and subionospherically propagating LF signal operated in Sicily, NSC at 45.90, kHz and VLF signal operated in Isola di Tavolara ICV at 20.27 kHz, with great circle distances of 953 km and 976 km, respectively. Geographical locations of transmitters and receiver site result that these short paths have many similarity. The main difference is in transmitter frequencies. In period from 2008 to February 2014 were selected around 200 events for further examination. In all selected examples amplitude and phase on VLF and LF signals were perturbed by occurrence of solar X-ray flares. This six years period covers minimum and maximum of solar activity. Also, simultaneous measurement of amplitude and phase on the VLF/LF signals during occurrence of solar flare were employed for constructing electron density profile versus altitude and also in a function of time over middle Europe.Comment: published in Serb.Astron.

Solar Radio Observation Using CALLISTO at the USO/PRL, Udaipur

This paper presents a detailed description of various subsystems of CALLISTO solar radio spectrograph installed at the USO/PRL. In the front-end system, a log periodic dipole antenna (LPDA) is designed for the frequency range of 40-900 MHz. In this paper LPDA design, its modifications, and simulation results are presented. We also present some initial observations taken by CALLISTO at Udaipur.Comment: Published in IEEE. https://ieeexplore.ieee.org/document/911866

Initial results of Husafell solar radio spectrograph

Observing the moon surface and subsurface materials using various radio frequencies is very important for investigating the physical properties of the moon. In particular, the frequency dependence of the dielectric constant of surface and subsurface materials provides information on the density profile. Because the dielectric constant is identified by measuring the reflectivity of the radio waves, we attempted to observe direct solar radio bursts in Iceland and reflected solar radio bursts in Iitate simultaneously. A new solar radio spectrograph to observe solar radio bursts has been installed at Husafell station in Iceland. The spectrograph covers two frequency bands in the ranges of 18MHz to 38MHz and 190MHz to 350MHz. Since September 2004, several successful observations have been made: 30 events of Type-I, -II, -III, and -IV bursts have been found in data obtained between September 2004 and August 2005. The flux density of the solar radio bursts detected in this study was within the range of 10 to 100s.f.u. We previously confirmed that when strong solar burst phenomena occur in the UHF range, the reflected wave signal from the moon surface can be detected using the Iitate Planetary Radio Telescope, installed in Japan

Image Processing of Narrow Band Solar Eclipse Data Using Python and MaxIm DL

On July 2, 2019, a total solar eclipse (TSE) was observable from Chile and Argentina. In Chile, I worked alongside the Solar Wind Sherpas, an international group led by Dr. Shadia Habbal from the University of Hawai\u27i Institute for Astronomy, to make observations of the solar corona and gather information about its elemental composition. Narrow band data were collected for Fe XI, Fe XIV, and Ar X. Data collected during TSE observations can be used to help solve two puzzles in solar physics: the coronal heating problem and the mechanisms responsible for the fast and slow solar winds. Narrow band images were processed and analyzed with MaxIm DL and the process was replicated by code I wrote in Python. The goal for this project was to write image processing code in Python to recreate what the image processing package MaxIm DL does

Long-term evolution of the heliospheric magnetic field inferred from cosmogenic 44^{44}Ti activity in meteorites

Typical reconstructions of historic heliospheric magnetic field (HMF) $B_{\rm HMF}$ are based on the analysis of the sunspot activity, geomagnetic data or on measurement of cosmogenic isotopes stored in terrestrial reservoirs like trees ($^{14}$C) and ice cores ($^{10}$Be). The various reconstructions of $B_{\rm HMF}$ are however discordant both in strength and trend. Cosmogenic isotopes, which are produced by galactic cosmic rays (GCRs) impacting on meteoroids and whose production rate is modulated by the varying HMF convected outward by the solar wind, may offer an alternative tool for the investigation of the HMF in the past centuries. In this work, we aim to evaluate the long-term evolution of $B_{\rm HMF}$ over a period covering the past twenty-two solar cycles by using measurements of the cosmogenic $^{44}$Ti activity ($\tau_{1/2} = 59.2 \pm 0.6$ yr) measured in 20 meteorites which fell between 1766 and 2001. Within the given uncertainties, our result is compatible with a HMF increase from $4.87^{+0.24}_{-0.30}$ nT in 1766 to $6.83^{+0.13}_{-0.11}$ nT in 2001, thus implying an overall average increment of $1.96^{+0.43}_{-0.35}$ nT over 235 years since 1766 reflecting the modern Grand maximum. The $B_{\rm HMF}$ trend thus obtained is then compared with the most recent reconstructions of the near-Earth heliospheric magnetic field strength based on geomagnetic, sunspot number and cosmogenic isotope data.Comment: Accepted for publication in Astronomy and Astrophysic