CAPTURE CONDITIONS FOR STRANGELETS IN THE GEOMAGNETIC FIELD

2007 ◽  
Vol 16 (02n03) ◽  
pp. 501-508
Author(s):  
L. PAULUCCI ◽  
J. E. HORVATH ◽  
G. A. MEDINA-TANCO
Keyword(s):  
Cross Sections ◽  
Geomagnetic Field ◽  
Hadronic Matter ◽  
Alternative Methods ◽  
Number Range ◽  
The Earth ◽  
Total Ionization ◽  
Baryonic Number ◽  
Geomagnetic Cutoff ◽  
Adiabatic Motion

Strangelets coming from the interstellar medium are an interesting target in experiments searching for evidence of this hypothetic state of hadronic matter. For a stationary population of strangelets to be trapped by the geomagnetic field, these particles would have to fulfill certain conditions, namely having magnetic rigidities above the geomagnetic cutoff and below a certain threshold for adiabatic motion. For totally ionized strangelets these two conditions prevent them to be stably trapped if one considers that a similar mechanism resulting in the anomalous cosmic rays belt should also be responsible for strangelet trapping. The situation could be different if those particles could reach the earth with an effective charge less than total ionization, since it would lower the particle's magnetic rigidity, but cross sections are much too low to allow interstellar electronic recombination for strangelets in the low baryonic number range. If traces of strangelets are indeed measured as a component of the radiation belt, alternative methods for their capture have to be proposed.

LONG-TERM TRENDS IN COSMIC RAYS AND GEOMAGNETIC FIELD SECULAR VARIATIONS

2021 ◽  
Vol 44 ◽  
pp. 79-80
Author(s):  
A.G. Elias ◽  
◽  
B.S. Zossi ◽  
A.R. Gutierrez Falcon ◽  
E.S. Comedi ◽  
...  
Keyword(s):  
Cosmic Rays ◽  
Data Center ◽  
Geomagnetic Field ◽  
The Earth ◽  
Geomagnetic Cutoff Rigidity ◽  
Secular Variations ◽  
Geomagnetic Cutoff ◽  
Long Term Trends ◽  
Long Term Trend

Cosmic rays are modulated by solar and geomagnetic activity. In addition, the flux that arrives to the Earth is sensitive to the inner geomagnetic field through its effect on the geomagnetic cutoff rigidity, Rc. This field has been decaying globally at a rate of ~5% per century from at least 1840. However, due to its configuration and non-uniform trend around the globe, its secular variation during the last decades has induced negative and positive Rc trends depending on location. In the present work, the database from the World Data Center for Cosmic Rays (WDCCR) is used to analyze long-term trend variations linked to geomagnetic secular variations. This database includes more than 100 stations covering, some of them, almost seven decades since the 1950’s. Those stations spanning more than 20 years of data are selected for the present study in order to adequately filter solar activity effects.

Trajectory reconstruction in the Earth Magnetosphere using TS05 model and evaluation of geomagnetic cutoff in AMS-02 data

2016 ◽  
Author(s):  
Davide Grandi ◽  
Bruna Bertucci ◽  
Matteo Boschini ◽  
Stefano Della torre ◽  
Matteo Duranti ◽  
...  
Keyword(s):  
Trajectory Reconstruction ◽  
The Earth ◽  
Geomagnetic Cutoff

scholarly journals Radar Observations of Comet Nuclei and Comae

2005 ◽  
Vol 13 ◽  
pp. 763-763
Author(s):  
Donald B. Campbell ◽  
John K. Harmon ◽  
Micael C. Nolan ◽  
Steven J. Ostro
Keyword(s):  
Cross Sections ◽  
Cometary Nucleus ◽  
Size Distributions ◽  
Radar Systems ◽  
The Earth ◽  
Radar Cross Sections ◽  
Short Period ◽  
Grain Size Distributions ◽  
Resolution Imaging

Nine comets have been detected with either the Arecibo (12.6 cm wavelength) or Goldstone (3.5 cm) radar systems. Included are six nucleus detections and five detections of echoes from coma grains. The radar backscatter cross sections measured for the nuclei correlate well with independent estimates of their sizes and are indicative of surface densities in the range of 0.5 to 1.0 g cm-3. Like most asteroids, comets appear to have surfaces that are very rough at scales much larger than the radar wavelength. Coma echo models can explain the radar cross sections using grain size distributions that include a substantial population of cm-sized grains. A long term goal of the cometary radar program has been the high resolution imaging of a cometary nucleus. Eleven short period comets are potentially detectable over the next two decades a few of which may be suitable for imaging. We are always waiting for the arrival of a new comet with an orbit that brings it within 0.1 AU of the earth.

scholarly journals Eigenmode analysis of ballooning perturbations in the inner magnetosphere of the Earth

2007 ◽  
Vol 25 (6) ◽  
pp. 1391-1403 ◽  
Author(s):  
A. S. Parnowski
Keyword(s):  
Stability Criterion ◽  
Geomagnetic Field ◽  
Finite Conductivity ◽  
Nonlinear Structures ◽  
Magnetic Hydrodynamics ◽  
Longitudinal Displacement ◽  
Inner Magnetosphere ◽  
Transversal Displacement ◽  
The Earth ◽  
Eigenmode Analysis

Abstract. We analyze coupled Alfvén and slow magnetosonic eigenmodes in a dipole geomagnetic field with different ionospheric conductivities in the framework of ideal magnetic hydrodynamics (MHD) with finite pressure. We use numerical and, if possible, analytical methods to describe eigenmode frequencies, growth rates and eigenfunctions. The spectrum of Alfvén and slow magnetosonic modes is discrete and equidistant. The frequencies of the first Alfvén and slow magnetosonic eigenmodes are estimated as ~1 Hz and ~1 mHz, respectively. In the case of finite conductivity, periodic and aperiodic modes are separated and their interaction analyzed. It was shown that periodic and aperiodic perturbations can mutually transform into each other. A new flute stability criterion is derived (α~4.25), which is stricter than the Gold criterion (α=20/3). Here, as usual, α=−L/p dp/dL. For flute perturbations, the deviations of transversal displacement from a constant are calculated. An approximation for longitudinal displacement is derived. We determined the position of the main longitudinal peak, which can be responsible for nonlinear structures observed by Freja. An influence of nonlinear terms in pressure is estimated as well.

scholarly journals The Electron Impact Ionization Cross Sections of Methanol, Ethanol and 1-Propanol

Atoms ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 60 ◽  
Author(s):  
Yogesh Kumar ◽  
Manoj Kumar ◽  
Sachin Kumar ◽  
Rajeev Kumar
Keyword(s):  
Electron Impact ◽  
Cross Sections ◽  
Impact Ionization ◽  
Experimental Results ◽  
Oscillator Strengths ◽  
Ionization Cross ◽  
Total Ionization ◽  
Plane Wave Born Approximation ◽  
Ionization Cross Sections ◽  
Good Agreement

In the present investigation, the plane-wave Born approximation was employed to calculate the total ionization cross sections by electron impact of methanol, ethanol and 1-propanol from the threshold of ionization to 10 MeV. This method requires continuum generalized oscillator strengths (CGOSs). The two different semi-phenomenological expressions of CGOS, given by Mayol and Salvat and Weizsacker and Williams, along with approximated form of the continuum optical oscillator strength (COOS) by Khare et al. were used. Furthermore, the average of the above two CGOSs was also used. The calculated ionization cross sections were compared to the available previous theoretical results and experimental data. Out of three CGOSs, the present results with the average CGOS were found in good agreement with the available experimental results for all the considered molecules. Collision parameters CRP were also calculated from 0.1 to 100 MeV and the calculations were found to be in excellent agreement with the experimental results of Reike and Prepejchal.

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