New Scheme for Positron Accumulation in Ultrahigh Vacuum

Oshima, Nobuyuki; Kojima, Takao; Niigaki, M.; Mohri, A.; Komaki, K.; Yamazaki, Y.

doi:10.1103/physrevlett.93.195001

Cited by 45 publications

(34 citation statements)

References 30 publications

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“…27). There are a number of ways, both experimentally confirmed as well as schemes suggested on numerical or theoretical grounds, to produce and store (Oshima et al, 2004) positronium and antimatter, e.g. laser generated relativistic superthermal electrons interacting with high-Z materials (Liang et al, 1998), the trident process in conjunction with ultra-intense short laser pulses in plasmas (Berezhiani et al, 1992), pair production by circularly polarized waves in plasmas (Bulanov, 2004), laser-thin foil interactions (Shen and Meyer-ter-Vehn, 2001b;Shen and Yu, 2002), using Bose-Einstein condensation traps (Greaves et al, 1994;Surko et al, 1989) (see Surko and Greaves (2004) for an overview), and using fullerenes (Oohara and Hatakeyama, 2003).…”

Section: Pair Production In External Fieldsmentioning

confidence: 99%

Nonlinear collective effects in photon-photon and photon-plasma interactions

2006

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We consider strong-field effects in laboratory and astrophysical plasmas and high intensity laser and cavity systems, related to quantum electrodynamical (QED) photon-photon scattering. Current state-of-the-art laser facilities are close to reaching energy scales at which laboratory astrophysics will become possible. In such high energy density laboratory astrophysical systems, quantum electrodynamics will play a crucial role in the dynamics of plasmas and indeed the vacuum itself. Developments such as the free electron laser may also give a means for exploring remote violent events such as supernovae in a laboratory environment. At the same time, superconducting cavities have steadily increased their quality factors, and quantum non-demolition measurements are capable of retrieving information from systems consisting of a few photons. Thus, not only will QED effects such as elastic photon-photon scattering be important in laboratory experiments, it may also be directly measurable in cavity experiments. Here we describe the implications of collective interactions between photons and photonplasma systems. We give an overview of strong field vacuum effects, as formulated through the Heisenberg-Euler Lagrangian. Based on the dispersion relation for a single test photon travelling in a slowly varying background electromagnetic field, a set of equations describing the nonlinear propagation of an electromagnetic pulse on a radiation-plasma is derived. The stability of the governing equations is discussed, and it is shown using numerical methods that electromagnetic pulses may collapse and split into pulse trains, as well as be trapped in a relativistic electron hole. Effects, such as the generation of novel electromagnetic modes, introduced by QED in pair plasmas is described. Applications to laser-plasma systems and astrophysical environments are discussed.

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Section: Pair Production In External Fieldsmentioning

confidence: 99%

Nonlinear collective effects in photon-photon and photon-plasma interactions

2006

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“…The transfer efficiency reported here corresponds to an overall accumulation rate into the cryogenic UHV region of 7:6 1:4 10 3 e =s=mCi of 22 Na. This is superior to other UHV compatible positron accumulation schemes such as an electron plasma based approach [19], field ionization of Rydberg positronium [20], and resistive cooling [21], which have accumulation rates of 3:6 10 2 , 1:1 10 1 , and 3:3 10 ÿ2 e =s=mCi, respectively.…”

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confidence: 99%

New Source of Dense, Cryogenic Positron Plasmas

Jørgensen¹,

Amoretti²,

Bonomi³

et al. 2005

Phys. Rev. Lett.

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We have developed a new method, based on the ballistic transfer of preaccumulated plasmas, to obtain large and dense positron plasmas in a cryogenic environment. The method involves transferring plasmas emanating from a region with a low magnetic field (0.14 T) and relatively high pressure (10 ÿ9 mbar) into a 15 K Penning-Malmberg trap immersed in a 3 T magnetic field with a base pressure better than 10 ÿ13 mbar. The achieved positron accumulation rate in the high field cryogenic trap is more than one and a half orders of magnitude higher than the previous most efficient UHV compatible scheme. Subsequent stacking resulted in a plasma containing more than 1:2 10 9 positrons, which is a factor 4 higher than previously reported. Using a rotating wall electric field, plasmas containing about 20 10 6 positrons were compressed to a density of 2:6 10 10 cm ÿ3 . This is a factor of 6 improvement over earlier measurements.

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“…Cold electron plasmas confined in this type of traps are now being used in several applications, including cooling of highly charged ions, 13,14 cooling of antiprotons for antihydrogen production at CERN, 7,15,16 and for positron accumulation. 17 To broaden the range of these applications, long lifetime and high density electron plasma are necessary. At RIKEN, the electron plasma lifetime played an essential role in the positron accumulation 17 and in the production of slow highly charged ions (HCIs) using an electron/positron cooling scheme.…”

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confidence: 99%

“…17 To broaden the range of these applications, long lifetime and high density electron plasma are necessary. At RIKEN, the electron plasma lifetime played an essential role in the positron accumulation 17 and in the production of slow highly charged ions (HCIs) using an electron/positron cooling scheme. 13 In this scheme, cold positrons were used as a coolant for HCIs.…”

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Comparison of non-neutral electron plasma confinement in harmonic and rectangular potentials in a very dense regime

2013

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Comparison of non-neutral electron plasma confinement in harmonic and rectangular potentials in a very dense regime Confinement of high density electron plasmas in a strong uniform magnetic field was experimentally studied in a multi-ring trap (MRT). The trap was housed inside a bore tube and surrounded by a superconducting solenoid. A 5 T magnetic field was used to provide radial confinement while an electrostatic harmonic or rectangular potential well was used for axial confinement. For trapped electrons of N ¼ 1.2 Â 10 10 in a harmonic potential well (HPW) with the trap length of L T ¼ 320 mm, the plasma lifetime was about 10 4 s and it became much longer at lower N ¼ 4.5 Â 10 9. Such long holding times were achieved without application of rotating electric fields. Contrastingly, in a rectangular potential well (RPW), the plasma of N ¼ 1.2 Â 10 10 under the same trap length expanded to cover the whole Faraday Cup within 200 s, where its radial expansion rate was g ¼ 3.2 Â 10 À2 mm/s, which was 20 times faster than HPW. The lifetime for RPW became shorter with increasing L T and scaled as 1/[L T ] 2

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New Scheme for Positron Accumulation in Ultrahigh Vacuum

Cited by 45 publications

References 30 publications

Nonlinear collective effects in photon-photon and photon-plasma interactions

Nonlinear collective effects in photon-photon and photon-plasma interactions

New Source of Dense, Cryogenic Positron Plasmas

Comparison of non-neutral electron plasma confinement in harmonic and rectangular potentials in a very dense regime

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