1 the spinning magnet accelerator cosmic cerns and slacs robert sheldon april 12, 2001

1

The Spinning Magnet Accelerator

Cosmic CERNs and SLACs

Robert SheldonApril 12, 2001

2

Space Plasma Cyclotrons

3/27

The "resonance condition for a cyclotron and the need for synchronization.

The maximum energy determined by maximum gyroradius of pole magnet

Center feed, rim exit. Dipole=cyclotron but NOT a betatron.

The Synchro-Cyclotron

4/27Drift Motion in B-field Gradients

x

5/27The Stochastic Dipole Cyclotron

Universe has dipoles. Drift trapping more

robust than gyrotrap because of edges.

Stochastically driven has power at all freq.

Adiabatic heating from inward diffusion (3rd invariant violation).

Adiabatic central heating--> escaping flux is cooler.

Rim feed, center exit.

The center is filled with the magnet, limiting the energy.

Diffusion rate slows near the center, limiting the power.

PROPRO CONCON

6/27

Insufficiency of the SDC Although the radiation belts of the

earth have 10s MeV particles, either GeVs precipitate into the center, or keVs adiabatically escape, cooling off. From a Mars vantage point, the Earth dipole is a weak source of keV particles and atoms. Nor does adiabatic heating explain power law tails. The Dipole is a better trap than accelerator.

7/27

MeV electrons 10/14/96

8/271 MeV electron in T96 Cusp

9/27

The Quadrupole Cusp 2-Dipole interactions = Quadrupole. A

Dipole embedded in flowing plasma creates a quadrupole cusp.

How likely? About like binary stars. Quadrupole is both a drift+gyro trap. Q is center feed, rim exit. Hi E escape. Q has no center magnet permitting

higher maximum energies. Q is NOT adiabatic==> chaotic accel!

10/27Quadrupole Cosmic Scales

Planetary Magnetospheres

Stellar Heliospheres

Binary stars Galactic

magnetic fields Galaxy clusters

keV (Mercury) to MeV (Jupiter)

10 - 100 MeV as observed at Sun

1-10 GeV 10-100 GeV ?

TeV?

11

Plasma Linear Accelerators

12/27

13/27

Parallel Electric Fields Whipple, JGR 1977. Ne = Ni, quasi-neutrality

f d v f d v

f n A E kT

f n n A E kT n A E B E

nn kT kT

BB

E BE B

e i

e

i i i

3 3

0 0

0 1 0 1 1

0

1

1

0

0

2

exp( / )

( ) exp( / ) ( ) ( )

sinh exp

F

n

kTe ||E

14/27Heuristics for Parallel-Efield

15/27High Injection Density in Storms

16/27

Necessary Conditions Inhomogeneous strong B-field such

that grad-B drifts dominate over ExB Dipole field! Ubiquitous

Source of hot plasma Injected directly (accretion disks) Convected from elsewhere

(plasmasheet) Spinning central magnet? Result:

Rim feed, axial exit accelerator. Efficient

17/27

Herbig-Haro Objects: Stars with Accretion Disks

HH30

18/27Blazar and Schematic Jet

19/27Quasar & Microquasar Jets

Cygnus A

3C273

20/27

Quadrupole Electric Field: 1st Excited State of a Dipole B-field

+++

+

- - ---

- -- -

21/27

Can SLAC power jets? The maximum electric field of such a

system is limited by 2nd order forces ((FXB) X B). Using some typical numbers for YSO for magnetic field strength, we get limiting energies of keV - MeV.

Applying same formula to quasar jets, we get ~1 GeV. Precisely the value that explains observations!

Q: What does a black hole magnetosphere look like? How does plasma affect equil.?

22/27Preliminary Conclusions

Both mechanisms are topological Ubiquitous. Scale to all sizes.

Quadrupole cyclotrons = 2 dipoles Planets embedded in flowing plasma Opposing magnetic fields, e.g. binary stars Stars (galaxies) moving through a plasma

background Jets =accretion disks + spinning B-

fields. YSO, AGN, micro-quasars,Herbig-Haro Earth has half an accretion

disk=plasmasheet

23

The UAH Spinning Terrella Accelerator

24/27

Experimental Setup Bell jar, oil roughing

pump, HV power supply, Nd-B ceramic magnet

Needle valve used to control the pressure from 10-400 mTorr

Simple

25/27Negatively Biased Magnet

26/27

Arcs and Sparks

27/27Characteristics of Discharge

KeV of Voltage Discharge lasts 30 microseconds Calculated milliCoulombs of

charge Estimated nF capacitance of

magnetic field In better vacuum (or collisionless

plasma) potentials are limited by 2nd order plasma drifts

Result: Space charge accelerator

28/27

Some References

Sheldon & Spurrier, "The Spinning Terrella Experiment", Phys. Plasmas, 8, 1111-1118, 2001.

Sheldon, "The Bimodal Magnetosphere", Adv. Sp. Res., 25, 2347-2356, 2000.

Sheldon, Spence & Fennel, "Observation of 40keV field-aligned beams", Geophys. Res. Lett. 25, 1617-1620, 1998.

All at: http://cspar181.uah.edu/RbS/