Impact Of Solar Flares Research Articles

Machine Learning Classification Workflow and Datasets for Ionospheric VLF Data Exclusion

Machine learning (ML) methods are commonly applied in the fields of extraterrestrial physics, space science, and plasma physics. In a prior publication, an ML classification technique, the Random Forest (RF) algorithm, was utilized to automatically identify and categorize erroneous signals, including instrument errors, noisy signals, outlier data points, and the impact of solar flares (SFs) on the ionosphere. This data communication includes the pre-processed dataset used in the aforementioned research, along with a workflow that utilizes the PyCaret library and a post-processing workflow. The code and data serve educational purposes in the interdisciplinary field of ML and ionospheric physics science, as well as being useful to other researchers for diverse objectives.

Impact of solar flares and geomagnetic storms on earth’s IMF and solar wind velocity during the descending phase of solar cycle 24

Impact of solar flares and geomagnetic storms on earth’s IMF and solar wind velocity during the descending phase of solar cycle 24

Effects of the 10 September 2017 Solar Flare on the Density and Composition of the Ionosphere of Mars: Significance of Thermospheric Changes

AbstractThe impact of solar flares on the upper atmosphere of Mars presents an opportune environment for investigating the ionosphere's response to the rapid and high‐energy dynamics of our Sun, with implications for characterizing atmospheric escape and evolution. The ionosphere of Mars is strongly influenced both by the levels of ionizing solar irradiance it receives and the associated behavior of the neutral thermosphere within which it is embedded. Here, we characterize density and composition changes in the topside ionosphere of Mars due to the X8.2‐class solar flare on 10 September 2017 from MAVEN spacecraft observations roughly 90 min after the onset of flare irradiance at Mars, by which time the neutral thermosphere had experienced significant thermal expansion. By contrasting altitude and pressure‐based representations of the ionospheric changes during the flare with the neutral thermospheric changes in both representations and basic photochemical expectation, we interpret and quantify the ionospheric behavior through a lesser explored lens of the neutral thermosphere's response to a flare. We find that the high‐altitude ionospheric density enhancements during this flare are larger than many identified from other flares, and that the neutral thermosphere's expansion accounts for a majority of the cumulative ion density changes observed. The ion density and compositional changes exhibit corresponding behavior with the neutral thermosphere's changes from both thermal expansion and photochemical effects. The identified characteristics of the ionosphere's response to a solar flare provide observational benchmarks for assessing and aiding numerical modeling efforts in accurately reproducing the behavior of the environment of Mars.

Detection of Solar Flares from the Analysis of Signal-to-Noise Ratio Recorded by Digisonde at Mid-Latitudes

This work proposes a new indirect method to detect the impact of solar flares on ionospheric sounding measurements, i.e., on the signal-to-noise ratio of ionospheric reflected radio signals. The method allows us to detect and characterize the ionospheric absorption of high-frequency radio waves as a product of these energetic events. The detection is based on the estimation of the quiet conditions signal-to-noise ratio (SNR) pattern of the month and the subsequent comparison of this pattern with the SNR for the analyzed day. The method has been tested by using data from Ebro Observatory ionospheric station (DPS4D, EB040), but it can be applied to any other ionospheric station. At EB040, it can provide observational data to the international Service of Rapid Magnetic Variations (SRMV) to help confirm Sfe (Solar Flare Effects). To set up the method, we considered a data set of 262 solar flares that occurred during 2011–2014 and were observed during daylight hours at EB040 (17 X-class, 124 M-class, and 121 C-class). This led to impose a threshold of −20 dB in the SNR for at least four consecutive frequencies to confirm that a solar flare took place. The method is particularly sensitive for the detection of X-class solar flares, performs quite well with M-class events, and is even able to detect some C-class flares with high solar altitude angles. Furthermore, we studied some constraints that affect the detection of solar flares from the analysis of GOES-15 hard X-ray flux data about the considered events. For each flare, we computed its solar altitude angle at the time of the ionospheric sounding to get an estimation of its geoeffective irradiance, which had an effect on the local ionosphere. We can confirm that the method of detection is more effective with flares that present a solar elevation angle higher than 18.94°, a geoeffective hard X-ray irradiance above 3.30 × 10−6 W/m2, and a geoeffective hard X-ray radiant exposure higher than 1.61 × 10−3 J/m2, computed during the 5 min preceding the ionospheric sounding.

A New Pathway for Incorporating the Impact of Solar Flares and Other Space Activity into Climate Modelling

A recent development in climate research is the recognition that space activity such as solar flares, gamma ray bursts, supernovas etc. can have a significant impact on the Earth. The existing methods of modelling space activity do not model these phenomena explicitly. Instead, their effect on ionization rates is formulated and then built into existing climate models. In this paper, based on the authors’ earlier work, several analytical approaches for modelling a solar flare hitting the Earth are presented. These methods can also be used for modelling gamma-ray bursts or cosmic rays striking our planet. In addition, a method of calculating the total amount of radiation received during a solar flare is proposed. The future use of the proposed modelling approaches within comprehensive global climate models allows for explicit modelling of space activity and provides a new pathway for studying the possible effects of this activity on the Earth.

Photochemistry-emission coupled model for Europa and Ganymede

In the frame of the JUICE mission, preliminary studies of the Jupiter’s icy moons, such as Ganymede and Europa, are mandatory. The present paper aims at characterizing the impact of the solar UV flux and its variability on their atmospheres. The solar UV radiation is responsible for the photoionization, photodissociation, and photoexcitation processes within planetary atmospheres. A 1-D photoabsorption model has been developed for different observational geometries, on the basis of a neutral atmospheric model. Considering various production and loss mechanisms but also the transport of oxygen atoms, we estimate the red and green line emissions from photo impact-induced excitation only. These dayglow emissions can represent few percent of the global airglow emission, mainly dominated by electron-induced excitation in auroral regions. For limb viewing conditions, red line emission is bright enough to be detected from actual spectrometers, from 338 R to 408 R according to the solar activity. This is also the case for the green line with 8 R at limb viewing. Considering a different neutral atmosphere model, with an O2 column density 50% more important, leads to a 14% increase in the red line emissions for limb viewing close to the surface. This difference could be important enough to infer which neutral model is the most likely. However, uncertainties on the solar UV flux might also prevent to constrain the O2 column density when using ground-based observations in the visible only. The impact of solar flares on the red line emissions for Europa has also been investigated within a planetary space weather context.

The Impact of Solar Flares and Cosmic Rays on Atmospheric Decay

The Impact of Solar Flares and Cosmic Rays on Atmospheric Decay

Onboard GRB trigger algorithms of SVOM-GRM

The Gamma-Ray Monitor (GRM) is a high energy detector onboard the future Chinese-French satellite named the Space-based multi-band astronomical Variable Object Monitor which is dedicated to studies of gamma-ray bursts (GRBs). This paper presents an investigation of the algorithms that look for GRBs by searching for a significant increase in the photon count rate for the computer onboard GRM. The trigger threshold and trigger efficiency, which are based on a given sample of GRBs, are calculated with the algorithms. The trigger characteristics of onboard instruments GRM and ECLAIRs are also analyzed. In addition, the impact of solar flares on GRM is estimated, and a method to distinguish solar flares from GRBs is investigated.

The impact of solar flares and magnetic storms on humans

The Sun shines, and Earth and its inhabitants benefit. But the Sun radiates more than light, and these radiations are variable over time scales of seconds to days. The consequences for people range from glorious celestial displays—auroras—to subtle but potentially damaging effects on the technological systems that are increasingly important for daily living. For example, electric power transmission systems and communication links have proven vulnerable to solar phenomena. And outside of Earth's protective atmosphere and magnetic shield, there is a small but genuine risk of a solar energetic particle burst that would be lethal to satellite sensors and command and control systems and astronauts.

Further evidence for impact of solar flares on potential gradient and air-earth current characteristics at high mountain stations

For the period February 1967–May 1969, a period of increasing solar activity, unrestricted substantiation was obtained of earlier results which had indicated that subsequent to Hα-flares potential gradient and air-earth current will increase significantly. A presupposition of this result is that the atmospheric electrical elements are recorded at stations with only minimal local climatic and aerosol physical disturbance factors, and that only meteorologically undisturbed days are used. It was ascertained that the exclusive use of fine weather days is of no influence on the results. The confirmed solar-terrestrial relation is even more pronounced when measurements are based on flares in the vicinity of the central meridian of the sun. It was further substantiated that the frequency of sferics pulses is significantly increased from the flare day on. As the cause for this a solar-triggered increase in thunderstorm frequency is suggested which, in turn, leads to an increase of the potential gradient and earth current. Proton flares have an effect analogous to that of Hα-flares. If Hα-flare key days are used on which significant changes were observed in the distribution of pressure over the northern hemisphere, a significant increase of potential gradient and air-earth current is found even with these flare key days. Thus for the first time a connection is made between solar-caused atmospheric electrical effects and synchronous global meteorological changes.