Instabilities of an electron cloud in a Penning trap

Paasche, P.; Angelescu, C.; Ananthamurthy, Sharath; Biswas, Debabrata; Valenzuela, T.; Werth, G.

doi:10.1140/epjd/e2002-00239-3

Cited by 23 publications

(16 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In a real trap with a cloud of electrons the radial and axial motion of the electrons are coupled due to Coulomb interactions as well as perturbations in the trap potential that originate from imperfections in the trap geometry. This leads to the presence of higher order frequencies measured as the motional resonances, in addition to the single particle frequencies described here [1,2,24,25]. The trapped electrons with temperature corresponding to a few eV, constitutes a non-neutral weakly coupled plasma with Coulomb coupling parameter ∼ 10 −4 , number density ∼ 10 +15 m −3 , Debye length ∼ 0.1 mm and plasma cloud of radius ∼ 4 mm.…”

Section: Theorymentioning

confidence: 70%

“…The details of this technique may be found in previous work [1,24,25,32]. The electrons generated from a thoriated tungsten filament are loaded into the trap and the filament current is then switched off while simultaneously setting the storage voltage, U 0 , that is applied between the end cap and ring electrodes.…”

Section: Measurement Of Confinement Timementioning

confidence: 99%

“…The procedure for obtaining the motional spectrum is described elsewhere and we will not elaborate this here [24,25,32]. The magnetic field obtained by measurement of the cyclotron frequency is plotted against the current in the electromagnet for a few measurements.…”

Section: Measurement Of Confinement Timementioning

confidence: 99%

See 2 more Smart Citations

Dependence of the confinement time of an electron plasma on the magnetic field in a quadrupole Penning trap

et al. 2017

View full text Add to dashboard Cite

A quadrupole Penning trap is used to confine electrons in weak magnetic fields. Perturbations due to space charge and imperfections in the trap geometry, as well as collisions with the background gas molecules, lead to loss of the electrons from the trap. We present in this work the results on measurements of the electron confinement time and its dependence on the magnetic field in a quadrupolar Penning trap. We describe a method to measure the confinement time of an electron cloud under weak magnetic fields (0.01 T -0.1 T). This time is found to scale as τ ∝ B 1.41 in variance with the theoretically expected confinement time that scales as τ ∝ B 2 for trapped electrons that are lost through collisions with the neutrals present in the trap. A measurement of the expansion rate of the electron plasma in the trap through controlled variation of the trap voltage, yields expansion times that depend on the energy of escaping electrons. This is found to vary in our case in the scaling range B 0.32 to B 0.43 . Distorting the geometry of the trap, results in a marked change in the confinement time's dependence on the magnetic field. The results indicate that the confinement time of the electron cloud in the trap is limited by both, effects of collisions and perturbations that result in the plasma loss through expansion in the trap.

show abstract

Section: Theorymentioning

confidence: 70%

Section: Measurement Of Confinement Timementioning

confidence: 99%

See 1 more Smart Citation

Dependence of the confinement time of an electron plasma on the magnetic field in a quadrupole Penning trap

et al. 2017

View full text Add to dashboard Cite

show abstract

“…The different graphs, starting from above, are for increasing strength of the radial inhomogeneous field which is characterized by the parameter r 0 /R. Operating points at which trapping instabilities, arising from trap imperfections, occur are indicated It has been shown [9] that these instabilities occur when the condition…”

Section: Measurementsmentioning

confidence: 99%

A Penning trap with radial magnetic field

Angelescu

Werth

2007

Hyperfine Interact

View full text Add to dashboard Cite

A radial inhomogeneous magnetic field produced by counter-propagating currents in anti-Helmholtz configuration coils has been superimposed to a Penning trap. The confinement properties of electrons in such a trap have been studied experimentally. Without the radial B-field we find a number of operating conditions where instabilities occur, arising from higher order contributions to the quadrupolar trapping field. When we apply the radial field the trap properties remain essentially unchanged until the strength of this field at the boundary of the electron cloud is of the same order as the homogeneous Penning field. Then a sudden breakdown in the confinement appears. The experiments have been performed in low magnetic fields. The equations of motions of the trapped particles can be cast in a dimensionless form and our results can be considered as independent of the field strength.

show abstract

“…Brown and Gabrielse [4] have successfully tuned out anharmonicities thereby achieving unprecedented experimental precision in their studies on geonium. Subsequently, several groups [15][16][17][18][19][20] have studied in detail the occurrences of non-linear resonances in Paul traps. Sevugrajan and Menon [21] have used perturbation method to derive an analytical relationship describing the dependence of ion secular frequency on octupole and hexapole superpositions.…”

Section: Introductionmentioning

confidence: 99%

Numerical calculations of potential distribution in non-ideal quadrupole trap and simulations of anharmonic oscillations

Gupta

Rao

2008

Pramana - J Phys

View full text Add to dashboard Cite

A quadrupole ion trap consisting of electrode structures symmetric about zaxis is an important tool for conducting several precision experiments. In practice the field inside the trap does not remain purely quadrupolar, and can be calculated using numerical methods. We have used boundary element method to calculate the potential inside the truncated as well as symmetrically misaligned quadrupolar ion trap. The calculated potential values are fitted to multipole expansion and the weights of multipole moments have been evaluated by minimizing the least square deviation. The higher-order multipole contribution in the fabricated hyperbolic electrodes due to truncation and machining imperfections is discussed. Non-linear effects arising due to the superposition of octupole moment manifest as anharmonic oscillations of trapped ions in the non-ideal Paul trap. Theoretical simulations of non-linear effects have been carried out.

show abstract

Instabilities of an electron cloud in a Penning trap

Cited by 23 publications

References 2 publications

Dependence of the confinement time of an electron plasma on the magnetic field in a quadrupole Penning trap

Dependence of the confinement time of an electron plasma on the magnetic field in a quadrupole Penning trap

A Penning trap with radial magnetic field

Numerical calculations of potential distribution in non-ideal quadrupole trap and simulations of anharmonic oscillations

Contact Info

Product

Resources

About