Trajectories of charged particles trapped in Earth’s magnetic field

Ozturk, Mesude

doi:10.1119/1.3684537

Cited by 31 publications

(18 citation statements)

References 22 publications

(20 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…(e.g. Ozturk 2012;Zweibel 2013). It is therefore not safe to assume that the UHECRs are accelerated in the present source state; it is the history of the source over the shorter of the GZK time and the UHECR escape time that matters.…”

Section: Enhanced Activity In the Past?mentioning

confidence: 99%

Fornax A, Centaurus A, and other radio galaxies as sources of ultrahigh energy cosmic rays

Matthews

Bell

Blundell

et al. 2018

Monthly Notices of the Royal Astronomical Society: Letters

View full text Add to dashboard Cite

show abstract

Section: Enhanced Activity In the Past?mentioning

confidence: 99%

Fornax A, Centaurus A, and other radio galaxies as sources of ultrahigh energy cosmic rays

Matthews

Bell

Blundell

et al. 2018

Monthly Notices of the Royal Astronomical Society: Letters

View full text Add to dashboard Cite

show abstract

“…The Newton‐Lorentz equation (with zero electrical field) is used to track the ion motion along the field. We applied the logic of Öztürk's () numerical approach (for nonrelativistic particles) and expanded the code in order to initiate ion motion at any location instead of the starting from the equatorial plane. The equation of motion is as follows:

\begin{matrix} lefttrue \\ \frac{d (m v)}{italicdt} = q E (boldr) + q v \otimes B (boldr) \\ \frac{italicdx}{italicdt} = v_{x}, \frac{italicdy}{italicdt} = v_{y}, \frac{italicdz}{italicdt} = v_{z}, \end{matrix}

where we take the electric field to be zero ( E = 0) and assume an axisymmetric (dipole) magnetic field.…”

Section: Methodsmentioning

confidence: 99%

Low‐Altitude Emission of Energetic Neutral Atoms: Multiple Interactions and Energy Loss

et al. 2017

View full text Add to dashboard Cite

Low‐altitude emissions (LAEs) are the energetic neutral atom (ENA) signature of ring current ions precipitating along the magnetic field to an altitude of 200–800 km. This altitude region is considered to be “optically thick” because ring current ions undergo multiple charge changing interactions (MCCIs) with Earth's dense oxygen exosphere. While each interaction involves an energy loss of ~36 eV, no prior study has determined the accumulated energy lost by 1–100 keV H+ emerging as LAEs. We have developed a 2‐D model with a geomagnetic dipole that captures the net effects in energy loss and pitch angle evolution as a result of MCCIs without the computational requirements of a full Monte Carlo simulation. Dependent on the amount of latitudinal migration, the energy loss is greater than 20% for ions below 60 keV for equatorward moving particles (30 keV for poleward). Since the ENA travels ballistically across a geomagnetic dipole, upon reionization, ion velocity along the local field increases (antiparallel in the northern hemisphere). Redirecting the particle upward through MCCIs is most effective during poleward ENA motion. The net effect is to redirect precipitating ions (below 2,500 km) to eventually emerge from the optically thick region either as an ion or ENA. Precipitation is a joint ion‐neutral process, affecting both the energy and pitch angle distribution through the transverse motion of ENA segments in a converging field. For particles that enter the MCCI regime, the energy loss and evolution of the pitch angle distribution must be considered within a realistic magnetic field.

show abstract

“…For a distribution N of particles with pitch angles in the interval

[θ_{l}, \frac{π}{2}]

( θ l is the boundary of the loss cone), the time dependence of N is governed by

\frac{∂N (θ)}{∂t} = - \frac{\partial}{∂θ} \cdot ((), (〈〉, \frac{ΔΘ}{ΔT}) N (θ)) + \frac{1}{2} \frac{\partial^{2}}{\partial θ^{2}} \cdot ((), (〈〉, \frac{{(ΔΘ)}^{2}}{ΔT}) N (θ)),

where ΔΘ is the variation in pitch angle of a test particle. The moments

〈 \frac{ΔΘ}{ΔT} 〉

and

〈 \frac{{(ΔΘ)}^{2}}{ΔT} 〉

were calculated using a test particle model, assuming a dipolar magnetic field as given by Öztürk []:

B (\overset{r}{true}) = \frac{μ_{0}}{4 π} ((), \frac{3 \overset{r}{true} (\overset{M}{true} \cdot \overset{r}{true})}{{\overset{r}{true}}^{5}} - \frac{\overset{M}{true}}{{\overset{r}{true}}^{3}}) .

…”

Section: Methodsmentioning

confidence: 99%

Using orbital tethers to remediate geomagnetic radiation belts

2016

View full text Add to dashboard Cite

The Van Allen radiation belts pose a hazard to spacecraft and astronauts, and similar radiation belts around other planets pose a hazard to interplanetary probes. We discuss a method of remediating these radiation belts first proposed by Danilov and Vasilyev, and recently improved by Hoyt, Minor, and Cash, where a long, charged tether is placed in orbit inside a radiation belt. In this approach, an electric field of the tether scatters the belt particles into a pitch angle loss cone leading to absorption of the particles in the atmosphere. A test particle calculation is presented which computes the scattered pitch angle of belt particles as a function of initial pitch angle and gyrophase for different particle energies. The moments of the resulting distribution of scattered angle versus initial pitch angle are used to compute the number density of the belt as a function of time using a Fokker‐Planck diffusion approximation. Finally, we use the characteristic timescales of scattering for particles of different energies to discuss the feasibility of using such a system of tethers as a long and short‐term remediation solution.

show abstract

Trajectories of charged particles trapped in Earth’s magnetic field

Cited by 31 publications

References 22 publications

Fornax A, Centaurus A, and other radio galaxies as sources of ultrahigh energy cosmic rays

Fornax A, Centaurus A, and other radio galaxies as sources of ultrahigh energy cosmic rays

Low‐Altitude Emission of Energetic Neutral Atoms: Multiple Interactions and Energy Loss

Using orbital tethers to remediate geomagnetic radiation belts

Contact Info

Product

Resources

About