scholarly journals Understanding shock dynamics in the inner heliosphere with modeling and type II radio data: A statistical study

2013 ◽  
Vol 118 (8) ◽  
pp. 4711-4723 ◽  
Author(s):  
H. Xie ◽  
O. C. St. Cyr ◽  
N. Gopalswamy ◽  
D. Odstrcil ◽  
H. Cremades
Keyword(s):  
Statistical Study ◽  
Type Ii ◽  
Radio Data ◽  
Shock Dynamics ◽  
Inner Heliosphere

scholarly journals Understanding shock dynamics in the inner heliosphere with modeling and Type II radio data: The 2010-04-03 event

2012 ◽  
Vol 117 (A4) ◽  
pp. n/a-n/a ◽  
Author(s):  
H. Xie ◽  
D. Odstrcil ◽  
L. Mays ◽  
O. C. St. Cyr ◽  
N. Gopalswamy ◽  
...  
Keyword(s):  
Type Ii ◽  
Radio Data ◽  
Shock Dynamics ◽  
Inner Heliosphere

scholarly journals Estimate of Plasma Temperatures Across a CME-Driven Shock from a Comparison Between EUV and Radio Data

Solar Physics ◽  
2020 ◽  
Vol 295 (9) ◽  
Author(s):  
Federica Frassati ◽  
Salvatore Mancuso ◽  
Alessandro Bemporad
Keyword(s):  
Shock Wave ◽  
Compression Ratio ◽  
Emission Measure ◽  
Type Ii ◽  
Solar Dynamics Observatory ◽  
Radio Data ◽  
Shock Temperature ◽  
Post Shock ◽  
Dem Analysis ◽  
Solar Dynamics

Abstract In this work, we analyze the evolution of an EUV wave front associated with a solar eruption that occurred on 30 October 2014, with the aim of investigating, through differential emission measure (DEM) analysis, the physical properties of the plasma compressed and heated by the accompanying shock wave. The EUV wave was observed by the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO) and was accompanied by the detection of a metric Type II burst observed by ground-based radio spectrographs. The EUV signature of the shock wave was also detected in two of the AIA channels centered at 193 Å and 211 Å as an EUV intensity enhancement propagating ahead of the associated CME. The density compression ratio $X$ X of the shock as inferred from the analysis of the EUV data is $X \approx 1.23$ X ≈ 1.23 , in agreement with independent estimates obtained from the analysis of the Type II band-splitting of the radio data and inferred by adopting the upstream–downstream interpretation. By applying the Rankine–Hugoniot jump conditions under the hypothesis of a perpendicular shock, we also estimate the temperature ratio as $T_{\mathrm{D}}/T_{\mathrm{U}} \approx 1.55$ T D / T U ≈ 1.55 and the post-shock temperature as $T_{\mathrm{D}}\approx 2.75$ T D ≈ 2.75 MK. The modest compression ratio and temperature jump derived from the EUV analysis at the shock passage are typical of weak coronal shocks.

Large-scale electron solar wind parameters of the inner heliosphere with Parker Solar Probe/FIELDS

2020 ◽  
Author(s):  
Karine Issautier ◽  
Mingzhe Liu ◽  
Michel Moncuquet ◽  
Nicole Meyer-Vernet ◽  
Milan Maksimovic ◽  
...  
Keyword(s):  
Solar Wind ◽  
Large Scale ◽  
Statistical Study ◽  
Solar Wind Speed ◽  
The Sun ◽  
Solar Wind Parameters ◽  
Power Law Index ◽  
Probe Mission ◽  
Inner Heliosphere

<p>We present in situ properties of electron density and temperature in the inner heliosphere obtained during the three first solar encounters at 35 solar radii of the Parker Solar Probe mission. These preliminary results, recently shown by Moncuquet et al., ApJS, 2020, are obtained from the analysis of the plasma quasi-thermal noise (QTN) spectrum measured by the radio RFS/FIELDS instrument along the trajectories extending between 0.5 and 0.17 UA from the Sun, revealing different states of the emerging solar wind, five months apart. The temperature of the weakly collisional core population varies radially with a power law index of about -0.8, much slower than adiabatic, whereas the temperature of the supra-thermal population exhibits a much flatter radial variation, as expected from its nearly collisionless state. These measured temperatures are close to extrapolations towards the Sun of Helios measurements.</p><p>We also present a statistical study from these in situ electron solar wind parameters, deduced by QTN spectroscopy, and compare the data to other onboard measurements. In addition, we focus on the large-scale solar wind properties. In particular, from the invariance of the energy flux, a direct relation between the solar wind speed and its density can be deduced, as we have already obtained based on Wind continuous in situ measurements (Le Chat et al., Solar Phys., 2012). We study this anti-correlation during the three first solar encounters of PSP.</p>

scholarly journals Radio Data and Computer Simulations for Shock Waves Generated by Solar Flares

1980 ◽  
Vol 91 ◽  
pp. 251-255
Author(s):  
Alan Maxwell ◽  
Murray Dryer
Keyword(s):  
Shock Waves ◽  
Solar Corona ◽  
Computer Simulations ◽  
Solar Flares ◽  
Solar Radio ◽  
Radio Bursts ◽  
Type Ii ◽  
Fast Mode ◽  
Solar Radio Bursts ◽  
Radio Data

Solar radio bursts of spectral type II provide a prime diagnostic for the passage of shock waves, generated by solar flares, through the solar corona. In this investigation we have compared radio data on the shocks with computer simulations for the propagation of fast-mode MHD shocks through the solar corona. The radio data were recorded at the Harvard Radio Astronomy Station, Fort Davis, Texas. The computer simulations were carried out at NOAA, Boulder, Colorado.

scholarly journals Multi-spacecraft observations to study the shock extension in the inner heliosphere

2008 ◽  
Vol 4 (S257) ◽  
pp. 481-487
Author(s):  
Aline de Lucas ◽  
Rainer Schwenn ◽  
Eckart Marsch ◽  
Alisson Dal Lago ◽  
Alicia L. Clúa de Gonzalez ◽  
...  
Keyword(s):  
Shock Waves ◽  
Field Data ◽  
Statistical Study ◽  
Statistical Evaluation ◽  
Interplanetary Medium ◽  
Angular Separation ◽  
Interplanetary Coronal Mass Ejections ◽  
Magnetic Field Data ◽  
Cutoff Value ◽  
Inner Heliosphere

AbstractThe two Helios probes traveled at variable longitudinal and radial separations through the inner heliosphere. They collected most valuable high resolution plasma and magnetic field data for an entire solar cycle. The mission is still so successful that no other missions will collect the same kind of data in the next 20 years. One of the subjects studied after the success of the Helios mission was the identification of more than 390 shock waves driven by Interplanetary Coronal Mass Ejections (ICMEs). Combining the data from both probes, we make a statistical study for the extension of the shock waves in the interplanetary medium. For longitudinal separations of 90° we found a cutoff value at this angular separation. A shock has 50% of chance to be observed by both probes and the same probability for not being observed by two spacecrafts at the same time, when the angle between them is around 90°. We describe the dependence of the probability for shocks to be observed by both probes with decreasing spacecraft separation. Including plasma data from the ISEE-3 and IMP-8 spacecrafts improves our statistical evaluation substantially.

Radial Evolution of Inverted Heliospheric Magnetic Field Between 0.3 and 1 AU

2020 ◽  
Author(s):  
Allan Macneil ◽  
Mathew Owens ◽  
Robert Wicks ◽  
Mike Lockwood ◽  
Matthew Lang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Solar Corona ◽  
Radial Velocity ◽  
Statistical Study ◽  
Heliospheric Magnetic Field ◽  
Radial Evolution ◽  
Inner Heliosphere

<p>Local inversions, or ‘switchbacks’, in the heliospheric magnetic field (HMF) have recently been identified as prominent features in the inner heliosphere through observations by Parker Solar Probe. These inversions coincide with spikes in radial velocity, and have been interpreted as possibly being the result of jets originating in the corona. While magnetic inversions with similar properties to these jets have also been observed by Helios around its perihelion of ~0.3 AU, inversions with a range of properties and scales have long been studied at distances of 1 AU and beyond. The processes which form the inversions seen outside of 0.3 AU, and whether they are a result of solar wind formation in the solar corona or the transport of solar wind through the heliosphere, are not clear. We present a statistical study on the occurrence of inverted heliospheric magnetic field using Helios 1 observations spanning heliocentric distances 0.3—1 AU. The evolution of inversion occurrence allows us to identify probable locations in the heliosphere where inversions may be produced. Based on these results, we make suggestions as to which processes are most likely responsible for inverted HMF observed between 0.3 and 1 AU.</p>

A statistical study of CMEs associated with metric type II bursts

2003 ◽  
Vol 30 (12) ◽  
Author(s):  
A. Lara ◽  
N. Gopalswamy ◽  
S. Nunes ◽  
G. Muñoz ◽  
S. Yashiro
Keyword(s):  
Statistical Study ◽  
Type Ii ◽  
Type Ii Bursts

scholarly journals Studies on Longer Wavelength Type II Radio Bursts Associated with Flares and CMEs during the Rise and Decay Phase of 23rd Solar Cycle

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
V. Vasanth ◽  
S. Umapathy
Keyword(s):  
Solar Cycle ◽  
Statistical Study ◽  
Decay Phase ◽  
Radio Bursts ◽  
Type Ii ◽  
23Rd Solar Cycle ◽  
Type Ii Radio Bursts ◽  
The Mean ◽  
Type Ii Bursts ◽  
Rise Phase

A statistical study on the properties of CMEs and flares associated with DH-type II bursts in the 23rd solar cycle during the period 1997–2008 is carried out. A sample of 229 events from our recent work is used for the present study (Vasanth and Umapathy, 2013). The collected events are divided into two groups as (i) solar cycle rise phase events and (ii) solar cycle decay phase events. The properties of CMEs in the two groups were compared and the results are presented. It is noted that there is no difference in the properties of type II burst like start frequency and end frequency between the solar cycle rise phase events and decay phase events. The mean CME speed of solar cycle decay phase events (1373 km s−1) is slightly higher than the solar cycle rise phase events (1058 km s−1). The mean CME acceleration of solar cycle decay phase events (−15.18 m s−2) is found to be higher than that of the solar cycle rise phase events (−1.32 m s−2). There exists good correlation between (i) CME speed and width and (ii) CME speed and acceleration for solar cycle decay phase events (R=0.79, R=-0.80) compared to solar cycle rise phase events (R=0.60, R=-0.57). These results indicate that the type II bursts parameters do not depend upon the time of appearance in the solar cycle.

scholarly journals Tracking the Source of Solar Type II Bursts through Comparisons of Simulations and Radio Data

2021 ◽  
Vol 922 (2) ◽  
pp. 203
Author(s):  
Alexander M. Hegedus ◽  
Ward B. Manchester ◽  
Justin C. Kasper
Keyword(s):  
Wind Waves ◽  
Solar Energetic Particle ◽  
Test Case ◽  
Type Ii ◽  
Radio Data ◽  
Synthetic Spectra ◽  
Type Ii Radio Bursts ◽  
Solar Type ◽  
Type Ii Bursts ◽  
Eastern Edge

Abstract The most intense solar energetic particle events are produced by coronal mass ejections (CMEs) accompanied by intense type II radio bursts below 15 MHz. Understanding where these type II bursts are generated relative to an erupting CME would reveal important details of particle acceleration near the Sun, but the emission cannot be imaged on Earth due to distortion from its ionosphere. Here, a technique is introduced to identify the likely source location of the emission by comparing the dynamic spectrum observed from a single spacecraft against synthetic spectra made from hypothesized emitting regions within a magnetohydrodynamic (MHD) numerical simulation of the recreated CME. The radio-loud 2005 May 13 CME was chosen as a test case, with Wind/WAVES radio data being used to frame the inverse problem of finding the most likely progression of burst locations. An MHD recreation is used to create synthetic spectra for various hypothesized burst locations. A framework is developed to score these synthetic spectra by their similarity to the type II frequency profile derived from the Wind/WAVES data. Simulated areas with 4× enhanced entropy and elevated de Hoffmann–Teller velocities are found to produce synthetic spectra similar to spacecraft observations. A geometrical analysis suggests the eastern edge of the entropy-derived shock around (−30°, 0°) was emitting in the first hour of the event before falling off, and the western/southwestern edge of the shock centered around (6°, −12°) was a dominant area of radio emission for the 2 hr of simulation data out to 20 solar radii.

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