Variabilities in the solar wind cause disturbances throughout the heliosphere on all temporal and spatial scales, which leads to changeable space weather. As a view of space weather forecasting, in particular, it is important to know direct and indirect causes modulating the space environment near t...
Variabilities in the solar wind cause disturbances throughout the heliosphere on all temporal and spatial scales, which leads to changeable space weather. As a view of space weather forecasting, in particular, it is important to know direct and indirect causes modulating the space environment near the Earth in advance. Recently, there are discussions on a role of the interaction of the solar wind with Mercury in affecting the solar wind velocity in the Earth's neighborhood during its inferior conjunctions. In this study we investigate a question of whether other parameters describing the space environment near the Earth are modulated by the inner planets' wake, by examining whether the interplanetary magnetic field and the proton density in the solar wind observed by the Advanced Composition Explorer (ACE) spacecraft, and the geomagnetic field via the Dst index and Auroral Electrojet index (AE index) are dependent upon the relative position of the inner planets. We find there are indeed apparent variations. For example, the mean variations of the geomagnetic fields measured in the Earth's neighborhood apparently have varied with a timescale of about 10 to 25 days. Those variations in the parameters we have studied, however, turn out to be a part of random fluctuations and have nothing to do with the relative position of inner planets. Moreover, it is found that variations of the proton density in the solar wind, the Dst index, and the AE index are distributed with the Gaussian distribution. Finally, we point out that some of properties in the behavior of the random fluctuation are to be studied.
Variabilities in the solar wind cause disturbances throughout the heliosphere on all temporal and spatial scales, which leads to changeable space weather. As a view of space weather forecasting, in particular, it is important to know direct and indirect causes modulating the space environment near the Earth in advance. Recently, there are discussions on a role of the interaction of the solar wind with Mercury in affecting the solar wind velocity in the Earth's neighborhood during its inferior conjunctions. In this study we investigate a question of whether other parameters describing the space environment near the Earth are modulated by the inner planets' wake, by examining whether the interplanetary magnetic field and the proton density in the solar wind observed by the Advanced Composition Explorer (ACE) spacecraft, and the geomagnetic field via the Dst index and Auroral Electrojet index (AE index) are dependent upon the relative position of the inner planets. We find there are indeed apparent variations. For example, the mean variations of the geomagnetic fields measured in the Earth's neighborhood apparently have varied with a timescale of about 10 to 25 days. Those variations in the parameters we have studied, however, turn out to be a part of random fluctuations and have nothing to do with the relative position of inner planets. Moreover, it is found that variations of the proton density in the solar wind, the Dst index, and the AE index are distributed with the Gaussian distribution. Finally, we point out that some of properties in the behavior of the random fluctuation are to be studied.
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가설 설정
In this study we investigate a question of whether other parameters describing the space environment near the Earth are modulated by the inner planets’ wake.
3 as shown in Fig. 2. Magnetic field strengths measured in the vicinity of the Earth are also considered as a random fluctuation as in the solar wind velocity. In Fig.
In this study we investigate a question of whether other parameters describing the space environment near the Earth are modulated by the inner planets’ wake, by examining whether properties of the interplanetary magnetic field and the proton density in the solar wind observed by the ACE spacecraft, and of the geomagnetic field are subject to the relative position of the inner planets.
제안 방법
19 meters from the center of the spacecraft at opposite sides along the ±Y axes of the spacecraft. The instrument returns 6 magnetic field vector measurements each second, divided between the two sensors, with onboard snapshot and FFT buffers to enhance the high-frequency resolution. Magnetic field vectors are given in the Radial Tangential Normal (RTN), Geocentric Solar Ecliptic (GSE), and Geocentric Solar Magnetospheric (GSM) coordinate systems.
Magnetic field vectors are given in the Radial Tangential Normal (RTN), Geocentric Solar Ecliptic (GSE), and Geocentric Solar Magnetospheric (GSM) coordinate systems. For this particular analysis, we adopt field values in the GSM coordinate system, where the X-axis is parallel to the EarthSun line and Z-axis is the projection of dipole axis on the YZ plane of the GSE coordinate system, the Z-axis of the GSE coordinate system being the ecliptic north pole. Data have been taken from the ACE Science Center website1.
Variations of the proton density in the solar wind, the Dst index, and the AE index are distributed with the Gaussian distribution. One might wish to perform a systematic statistical study of the characteristics of the distribution. We conclude, finally, that the inner planets cannot affect the Earth’s neighborhood during its inferior conjunctions and the observed variations are randomly distributed noise, whose behavior can be further studied in terms of the distribution and/or in the frequency domain.
대상 데이터
The sensors are mounted on booms extending 4.19 meters from the center of the spacecraft at opposite sides along the ±Y axes of the spacecraft.
이론/모형
6. Histograms of the number density of protons in the solar wind and their best fits obtained using the Gaussian function. From top to bottom, the histograms are obtained from the variation in the number density of the case of the inferior conjunctions with Venus, the case of the superior conjunctions, the randomly chosen case, respectively.
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